Ext JS 4.2.0 Sencha Docs

String

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String is a global object that may be used to construct String instances.

String objects may be created by calling the constructor new String(). The String object wraps JavaScript's string primitive data type with the methods described below. The global function String() can also be called without new in front to create a primitive string. String literals in JavaScript are primitive strings.

Because JavaScript automatically converts between string primitives and String objects, you can call any of the methods of the String object on a string primitive. JavaScript automatically converts the string primitive to a temporary String object, calls the method, then discards the temporary String object. For example, you can use the String.length property on a string primitive created from a string literal:

s_obj = new String(s_prim = s_also_prim = "foo");

s_obj.length;       // 3
s_prim.length;      // 3
s_also_prim.length; // 3
'foo'.length;       // 3
"foo".length;       // 3

(A string literal is denoted with single or double quotation marks.)

String objects can be converted to primitive strings with the valueOf method.

String primitives and String objects give different results when evaluated as JavaScript. Primitives are treated as source code; String objects are treated as a character sequence object. For example:

s1 = "2 + 2";               // creates a string primitive
s2 = new String("2 + 2");   // creates a String object
eval(s1);                   // returns the number 4
eval(s2);                   // returns the string "2 + 2"
eval(s2.valueOf());         // returns the number 4

Character access

There are two ways to access an individual character in a string. The first is the charAt method:

return 'cat'.charAt(1); // returns "a"

The other way is to treat the string as an array, where each index corresponds to an individual character:

return 'cat'[1]; // returns "a"

The second way (treating the string as an array) is not part of ECMAScript 3. It is a JavaScript and ECMAScript 5 feature.

In both cases, attempting to set an individual character won't work. Trying to set a character through charAt results in an error, while trying to set a character via indexing does not throw an error, but the string itself is unchanged.

Comparing strings

C developers have the strcmp() function for comparing strings. In JavaScript, you just use the less- than and greater-than operators:

var a = "a";
var b = "b";
if (a < b) // true
    print(a + " is less than " + b);
else if (a > b)
    print(a + " is greater than " + b);
else
    print(a + " and " + b + " are equal.");

A similar result can be achieved using the localeCompare method inherited by String instances.

Documentation for this class comes from MDN and is available under Creative Commons: Attribution-Sharealike license.

Available since: 1.1.0

Defined By

Properties

Reflects the length of the string. ...

Reflects the length of the string.

This property returns the number of code units in the string. UTF-16, the string format used by JavaScript, uses a single 16-bit code unit to represent the most common characters, but needs to use two code units for less commonly-used characters, so it's possible for the value returned by length to not match the actual number of characters in the string.

For an empty string, length is 0.

var x = "Netscape";
var empty = "";

console.log("Netspace is " + x.length + " code units long");
console.log("The empty string is has a length of " + empty.length); // should be 0

Available since: 4.0.0

Defined By

Methods

new( value ) : String
Creates new String object. ...

Creates new String object.

Available since: 4.0.0

Parameters

  • value : Object

    The value to wrap into String object.

Returns

( index ) : String
Returns the character at the specified index. ...

Returns the character at the specified index.

Characters in a string are indexed from left to right. The index of the first character is 0, and the index of the last character in a string called stringName is stringName.length - 1. If the index you supply is out of range, JavaScript returns an empty string.

The following example displays characters at different locations in the string "Brave new world":

var anyString="Brave new world";

document.writeln("The character at index 0 is '" + anyString.charAt(0) + "'");
document.writeln("The character at index 1 is '" + anyString.charAt(1) + "'");
document.writeln("The character at index 2 is '" + anyString.charAt(2) + "'");
document.writeln("The character at index 3 is '" + anyString.charAt(3) + "'");
document.writeln("The character at index 4 is '" + anyString.charAt(4) + "'");
document.writeln("The character at index 999 is '" + anyString.charAt(999) + "'");

These lines display the following:

The character at index 0 is 'B'
The character at index 1 is 'r'
The character at index 2 is 'a'
The character at index 3 is 'v'
The character at index 4 is 'e'
The character at index 999 is ''

The following provides a means of ensuring that going through a string loop always provides a whole character, even if the string contains characters that are not in the Basic Multi-lingual Plane.

var str = 'A\uD87E\uDC04Z'; // We could also use a non-BMP character directly
for (var i=0, chr; i < str.length; i++) {
    if ((chr = getWholeChar(str, i)) === false) {continue;} // Adapt this line at the top of

each loop, passing in the whole string and the current iteration and returning a variable to represent the individual character

    alert(chr);
}

function getWholeChar (str, i) {
    var code = str.charCodeAt(i);

    if (isNaN(code)) {
    return ''; // Position not found
    }
    if (code < 0xD800 || code > 0xDFFF) {
        return str.charAt(i);
    }
    if (0xD800 <= code && code <= 0xDBFF) { // High surrogate (could change last hex to 0xDB7F

to treat high private surrogates as single characters)

    if (str.length <= (i+1))  {
        throw 'High surrogate without following low surrogate';
    }
    var next = str.charCodeAt(i+1);
    if (0xDC00 > next || next > 0xDFFF) {
        throw 'High surrogate without following low surrogate';
    }
    return str.charAt(i)+str.charAt(i+1);
}
// Low surrogate (0xDC00 <= code && code <= 0xDFFF)
if (i === 0) {
    throw 'Low surrogate without preceding high surrogate';
}
var prev = str.charCodeAt(i-1);
if (0xD800 > prev || prev > 0xDBFF) { // (could change last hex to 0xDB7F to treat high private

surrogates as single characters)

  throw 'Low surrogate without preceding high surrogate';
}
return false; // We can pass over low surrogates now as the second component in a pair which we

have already processed }

While the second example may be more frequently useful for those wishing to support non-BMP characters (since the above does not require the caller to know where any non-BMP character might appear), in the event that one does wish, in choosing a character by index, to treat the surrogate pairs within a string as the single characters they represent, one can use the following:

function fixedCharAt (str, idx) {
    var ret = '';
    str += '';
    var end = str.length;

    var surrogatePairs = /[\uD800-\uDBFF][\uDC00-\uDFFF]/g;
    while ((surrogatePairs.exec(str)) != null) {
        var li = surrogatePairs.lastIndex;
        if (li - 2 < idx) {
            idx++;
        }
        else {
        break;
    }
}

if (idx >= end || idx < 0) {
    return '';
}

ret += str.charAt(idx);

if (/[\uD800-\uDBFF]/.test(ret) && /[\uDC00-\uDFFF]/.test(str.charAt(idx+1))) {
    ret += str.charAt(idx+1); // Go one further, since one of the "characters" is part of a

surrogate pair

}
return ret;
}

Available since: 4.0.0

Parameters

  • index : Number

    An integer between 0 and 1 less than the length of the string.

Returns

  • String

    Individual character from string.

( index ) : Number
Returns a number indicating the Unicode value of the character at the given index. ...

Returns a number indicating the Unicode value of the character at the given index.

Unicode code points range from 0 to 1,114,111. The first 128 Unicode code points are a direct match of the ASCII character encoding.

Note that charCodeAt will always return a value that is less than 65,536. This is because the higher code points are represented by a pair of (lower valued) "surrogate" pseudo-characters which are used to comprise the real character. Because of this, in order to examine or reproduce the full character for individual characters of value 65,536 and above, for such characters, it is necessary to retrieve not only charCodeAt(i), but also charCodeAt(i+1) (as if examining/reproducing a string with two letters). See example 2 and 3 below.

charCodeAt returns NaN if the given index is not greater than 0 or is greater than the length of the string.

Backward Compatibility with JavaScript 1.2

The charCodeAt method returns a number indicating the ISO-Latin-1 codeset value of the character at the given index. The ISO-Latin-1 codeset ranges from 0 to 255. The first 0 to 127 are a direct match of the ASCII character set.

Example 1: Using charCodeAt

The following example returns 65, the Unicode value for A.

"ABC".charCodeAt(0) // returns 65

Example 2: Fixing charCodeAt to handle non-Basic-Multilingual-Plane characters if their presence earlier in the string is unknown

This version might be used in for loops and the like when it is unknown whether non-BMP characters exist before the specified index position.

function fixedCharCodeAt (str, idx) {
    // ex. fixedCharCodeAt ('\uD800\uDC00', 0); // 65536
    // ex. fixedCharCodeAt ('\uD800\uDC00', 1); // 65536
    idx = idx || 0;
    var code = str.charCodeAt(idx);
    var hi, low;
    if (0xD800 <= code && code <= 0xDBFF) { // High surrogate (could change last hex to 0xDB7F to treat high private surrogates as single characters)
        hi = code;
        low = str.charCodeAt(idx+1);
        if (isNaN(low)) {
            throw 'High surrogate not followed by low surrogate in fixedCharCodeAt()';
        }
        return ((hi - 0xD800) * 0x400) + (low - 0xDC00) + 0x10000;
    }
    if (0xDC00 <= code && code <= 0xDFFF) { // Low surrogate
    // We return false to allow loops to skip this iteration since should have already handled

high surrogate above in the previous iteration

        return false;
    }
    return code;
}

Example 3: Fixing charCodeAt to handle non-Basic-Multilingual-Plane characters if their presence earlier in the string is known

function knownCharCodeAt (str, idx) {
    str += '';
    var code,
    end = str.length;

    var surrogatePairs = /[\uD800-\uDBFF][\uDC00-\uDFFF]/g;
    while ((surrogatePairs.exec(str)) != null) {
        var li = surrogatePairs.lastIndex;
        if (li - 2 < idx) {
            idx++;
        }
        else {
            break;
        }
    }

    if (idx >= end || idx < 0) {
        return NaN;
    }

    code = str.charCodeAt(idx);

    var hi, low;
    if (0xD800 <= code && code <= 0xDBFF) {
        hi = code;
        low = str.charCodeAt(idx+1); // Go one further, since one of the "characters" is part of

a surrogate pair

        return ((hi - 0xD800) * 0x400) + (low - 0xDC00) + 0x10000;
    }
    return code;
}

Available since: 4.0.0

Parameters

  • index : Number

    An integer greater than 0 and less than the length of the string; if it is not a number, it defaults to 0.

Returns

  • Number

    Value between 0 and 65535.

( strings ) : String
Combines combines the text from one or more strings and returns a new string. ...

Combines combines the text from one or more strings and returns a new string. Changes to the text in one string do not affect the other string.

The following example combines strings into a new string.

var hello = "Hello, ";
console.log(hello.concat("Kevin", " have a nice day.")); // Hello, Kevin have a nice day.

Available since: 4.0.0

Parameters

  • strings : String...

    The strings to concatenate.

Returns

  • String

    Result of both strings.

( numbers ) : String
Returns a string created by using the specified sequence of Unicode values. ...

Returns a string created by using the specified sequence of Unicode values.

This method returns a string and not a String object.

Because fromCharCode is a static method of String, you always use it as String.fromCharCode(), rather than as a method of a String object you created.

Although most common Unicode values can be represented in a fixed width system/with one number (as expected early on during JavaScript standardization) and fromCharCode() can be used to return a single character for the most common values (i.e., UCS-2 values which are the subset of UTF-16 with the most common characters), in order to deal with ALL legal Unicode values, fromCharCode() alone is inadequate. Since the higher code point characters use two (lower value) "surrogate" numbers to form a single character, fromCharCode() can be used to return such a pair and thus adequately represent these higher valued characters.

Be aware, therefore, that the following utility function to grab the accurate character even for higher value code points, may be returning a value which is rendered as a single character, but which has a string count of two (though usually the count will be one).

// String.fromCharCode() alone cannot get the character at such a high code point
// The following, on the other hand, can return a 4-byte character as well as the
//   usual 2-byte ones (i.e., it can return a single character which actually has
//   a string length of 2 instead of 1!)
alert(fixedFromCharCode(0x2F804)); // or 194564 in decimal

function fixedFromCharCode (codePt) {
    if (codePt > 0xFFFF) {
        codePt -= 0x10000;
        return String.fromCharCode(0xD800 + (codePt >> 10), 0xDC00 +
        (codePt & 0x3FF));
    }
    else {
        return String.fromCharCode(codePt);
    }
}

The following example returns the string "ABC".

String.fromCharCode(65,66,67)

Available since: 4.0.0

Parameters

  • numbers : Number...

    A sequence of numbers that are Unicode values.

Returns

  • String

    String containing characters from encoding.

( searchValue, fromIndex ) : Number
Returns the index within the calling String object of the first occurrence of the specified value, or -1 if not found. ...

Returns the index within the calling String object of the first occurrence of the specified value, or -1 if not found.

Characters in a string are indexed from left to right. The index of the first character is 0, and the index of the last character of a string called stringName is stringName.length - 1.

"Blue Whale".indexOf("Blue")    // returns 0
"Blue Whale".indexOf("Blute")   // returns -1
"Blue Whale".indexOf("Whale",0) // returns 5
"Blue Whale".indexOf("Whale",5) // returns 5
"Blue Whale".indexOf("",9)      // returns 9
"Blue Whale".indexOf("",10)     // returns 10
"Blue Whale".indexOf("",11)     // returns 10

The indexOf method is case sensitive. For example, the following expression returns -1:

"Blue Whale".indexOf("blue")

Note that '0' doesn't evaluate to true and '-1' doesn't evaluate to false. Therefore, when checking if a specific string exists within another string the correct way to check would be:

"Blue Whale".indexOf("Blue") != -1 // true
"Blue Whale".indexOf("Bloe") != -1 // false

The following example uses indexOf and lastIndexOf to locate values in the string "Brave new world".

var anyString="Brave new world"

document.write("<P>The index of the first w from the beginning is " + anyString.indexOf("w"))          // Displays 8
document.write("<P>The index of the first w from the end is " + anyString.lastIndexOf("w"))      // Displays 10
document.write("<P>The index of 'new' from the beginning is " + anyString.indexOf("new"))        // Displays 6
document.write("<P>The index of 'new' from the end is " + anyString.lastIndexOf("new"))    // Displays 6

The following example defines two string variables. The variables contain the same string except that the second string contains uppercase letters. The first writeln method displays 19. But because the indexOf method is case sensitive, the string "cheddar" is not found in myCapString, so the second writeln method displays -1.

myString="brie, pepper jack, cheddar"
myCapString="Brie, Pepper Jack, Cheddar"
document.writeln('myString.indexOf("cheddar") is ' + myString.indexOf("cheddar"))
document.writeln('<P>myCapString.indexOf("cheddar") is ' + myCapString.indexOf("cheddar"))

The following example sets count to the number of occurrences of the letter x in the string str:

count = 0;
pos = str.indexOf("x");
while ( pos != -1 ) {
    count++;
    pos = str.indexOf("x",pos+1);
}

Available since: 4.0.0

Parameters

  • searchValue : String

    A string representing the value to search for.

  • fromIndex : Number

    The location within the calling string to start the search from. It can be any integer between 0 and the length of the string. The default value is 0.

Returns

  • Number

    Position of specified value or -1 if not found.

( searchValue, fromIndex ) : Number
Returns the index within the calling String object of the last occurrence of the specified value, or -1 if not found. ...

Returns the index within the calling String object of the last occurrence of the specified value, or -1 if not found. The calling string is searched backward, starting at fromIndex.

Characters in a string are indexed from left to right. The index of the first character is 0, and the index of the last character is stringName.length - 1.

"canal".lastIndexOf("a")   // returns 3
"canal".lastIndexOf("a",2) // returns 1
"canal".lastIndexOf("a",0) // returns -1
"canal".lastIndexOf("x")   // returns -1

The lastIndexOf method is case sensitive. For example, the following expression returns -1:

"Blue Whale, Killer Whale".lastIndexOf("blue")

The following example uses indexOf and lastIndexOf to locate values in the string "Brave new world".

var anyString="Brave new world"

// Displays 8
document.write("<P>The index of the first w from the beginning is " +
anyString.indexOf("w"))
// Displays 10
document.write("<P>The index of the first w from the end is " +
anyString.lastIndexOf("w"))
// Displays 6
document.write("<P>The index of 'new' from the beginning is " +
anyString.indexOf("new"))
// Displays 6
document.write("<P>The index of 'new' from the end is " +
anyString.lastIndexOf("new"))

Available since: 4.0.0

Parameters

  • searchValue : String

    A string representing the value to search for.

  • fromIndex : Number

    The location within the calling string to start the search from, indexed from left to right. It can be any integer between 0 and the length of the string. The default value is the length of the string.

Returns

( compareString ) : Number
Returns a number indicating whether a reference string comes before or after or is the same as the given string in so...

Returns a number indicating whether a reference string comes before or after or is the same as the given string in sort order.

Returns a number indicating whether a reference string comes before or after or is the same as the given string in sort order. Returns -1 if the string occurs earlier in a sort than compareString, returns 1 if the string occurs afterwards in such a sort, and returns 0 if they occur at the same level.

The following example demonstrates the different potential results for a string occurring before, after, or at the same level as another:

alert('a'.localeCompare('b')); // -1
alert('b'.localeCompare('a')); // 1
alert('b'.localeCompare('b')); // 0

Available since: 4.0.0

Parameters

  • compareString : String

    The string against which the referring string is comparing.

Returns

  • Number

    Returns -1 if the string occurs earlier in a sort than compareString, returns 1 if the string occurs afterwards in such a sort, and returns 0 if they occur at the same level.

( regexp ) : Array
Used to match a regular expression against a string. ...

Used to match a regular expression against a string.

If the regular expression does not include the g flag, returns the same result as regexp.exec(string).

If the regular expression includes the g flag, the method returns an Array containing all matches. If there were no matches, the method returns null.

The returned Array has an extra input property, which contains the regexp that generated it as a result. In addition, it has an index property, which represents the zero-based index of the match in the string.

In the following example, match is used to find "Chapter" followed by 1 or more numeric characters followed by a decimal point and numeric character 0 or more times. The regular expression includes the i flag so that case will be ignored.

str = "For more information, see Chapter 3.4.5.1";
re = /(chapter \d+(\.\d)*)/i;
found = str.match(re);
document.write(found);

This returns the array containing Chapter 3.4.5.1,Chapter 3.4.5.1,.1

"Chapter 3.4.5.1" is the first match and the first value remembered from (Chapter \d+(\.\d)*).

".1" is the second value remembered from (\.\d).

The following example demonstrates the use of the global and ignore case flags with match. All letters A through E and a through e are returned, each its own element in the array

var str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
var regexp = /[A-E]/gi;
var matches_array = str.match(regexp);
document.write(matches_array);

matches_array now equals ['A', 'B', 'C', 'D', 'E', 'a', 'b', 'c', 'd', 'e'].

Available since: 4.0.0

Parameters

  • regexp : RegExp

    A RegExp object. If a non-RegExp object obj is passed, it is implicitly converted to a RegExp by using new RegExp(obj).

Returns

  • Array

    Contains results of the match (if any).

( pattern, replacement ) : String
Used to find a match between a regular expression and a string, and to replace the matched substring with a new subst...

Used to find a match between a regular expression and a string, and to replace the matched substring with a new substring.

This method does not change the String object it is called on. It simply returns a new string.

To perform a global search and replace, either include the g flag in the regular expression or if the first parameter is a string, include g in the flags parameter.

The replacement string can include the following special replacement patterns:

Pattern Inserts
$$ Inserts a $.
$& Inserts the matched substring.
`$`` Inserts the portion of the string that precedes the matched substring.
$' Inserts the portion of the string that follows the matched substring.
$n or $nn Where n or nn are decimal digits, inserts the _n_th parenthesized submatch string, provided the first
argument was a RegExp object.

You can specify a function as the second parameter. In this case, the function will be invoked after the match has been performed. The function's result (return value) will be used as the replacement string. (Note: the above-mentioned special replacement patterns do not apply in this case.) Note that the function will be invoked multiple times for each full match to be replaced if the regular expression in the first parameter is global.

The arguments to the function are as follows:

Possible Name Supplied Value
str The matched substring. (Corresponds to $& above.)
p1, p2, ... The _n_th parenthesized submatch string, provided the first argument to replace was a RegExp object.
(Correspond to , , etc. above.)
offset The offset of the matched substring within the total string being examined. (For example, if the total string
was "abcd", and the matched substring was "bc", then this argument will be 1.)
s The total string being examined.

(The exact number of arguments will depend on whether the first argument was a RegExp object and, if so, how many parenthesized submatches it specifies.)

The following example will set newString to "XXzzzz - XX , zzzz":

function replacer(str, p1, p2, offset, s)
{
    return str + " - " + p1 + " , " + p2;
}
var newString = "XXzzzz".replace(/(X*)(z*)/, replacer);

In the following example, the regular expression includes the global and ignore case flags which permits replace to replace each occurrence of 'apples' in the string with 'oranges'.

var re = /apples/gi;
var str = "Apples are round, and apples are juicy.";
var newstr = str.replace(re, "oranges");
print(newstr);

In this version, a string is used as the first parameter and the global and ignore case flags are specified in the flags parameter.

var str = "Apples are round, and apples are juicy.";
var newstr = str.replace("apples", "oranges", "gi");
print(newstr);

Both of these examples print "oranges are round, and oranges are juicy."

In the following example, the regular expression is defined in replace and includes the ignore case flag.

var str = "Twas the night before Xmas...";
var newstr = str.replace(/xmas/i, "Christmas");
print(newstr);

This prints "Twas the night before Christmas..."

The following script switches the words in the string. For the replacement text, the script uses the and replacement patterns.

var re = /(\w+)\s(\w+)/;
var str = "John Smith";
var newstr = str.replace(re, ", ");
print(newstr);

This prints "Smith, John".

In this example, all occurrences of capital letters in the string are converted to lower case, and a hyphen is inserted just before the match location. The important thing here is that additional operations are needed on the matched item before it is given back as a replacement.

The replacement function accepts the matched snippet as its parameter, and uses it to transform the case and concatenate the hyphen before returning.

function styleHyphenFormat(propertyName)
{
    function upperToHyphenLower(match)
    {
        return '-' + match.toLowerCase();
    }
    return propertyName.replace(/[A-Z]/, upperToHyphenLower);
}

Given styleHyphenFormat('borderTop'), this returns 'border-top'.

Because we want to further transform the result of the match before the final substitution is made, we must use a function. This forces the evaluation of the match prior to the toLowerCase() method. If we had tried to do this using the match without a function, the toLowerCase() would have no effect.

var newString = propertyName.replace(/[A-Z]/, '-' + '$&'.toLowerCase());  // won't work

This is because '$&'.toLowerCase() would be evaluated first as a string literal (resulting in the same '$&') before using the characters as a pattern.

The following example replaces a Fahrenheit degree with its equivalent Celsius degree. The Fahrenheit degree should be a number ending with F. The function returns the Celsius number ending with C. For example, if the input number is 212F, the function returns 100C. If the number is 0F, the function returns -17.77777777777778C.

The regular expression test checks for any number that ends with F. The number of Fahrenheit degree is accessible to the function through its second parameter, p1. The function sets the Celsius number based on the Fahrenheit degree passed in a string to the f2c function. f2c then returns the Celsius number. This function approximates Perl's s///e flag.

function f2c(x)
{
    function convert(str, p1, offset, s)
    {
        return ((p1-32) * 5/9) + "C";
    }
    var s = String(x);
    var test = /(\d+(?:\.\d*)?)F\b/g;
    return s.replace(test, convert);
}

Available since: 4.0.0

Parameters

  • pattern : String/RegExp

    Either a string or regular expression pattern to search for.

  • replacement : String/Function

    Either string or function:

    • The String to replace the pattern with. Number of special replacement patterns are supported; see the "Specifying a string as a parameter" section above.
    • A function to be invoked to create the replacement. The arguments supplied to this function are described in the "Specifying a function as a parameter" section above.

Returns

  • String

    String of matched replaced items.

( beginSlice, endSlice ) : String
Extracts a section of a string and returns a new string. ...

Extracts a section of a string and returns a new string.

slice extracts the text from one string and returns a new string. Changes to the text in one string do not affect the other string.

slice extracts up to but not including endSlice. string.slice(1,4) extracts the second character through the fourth character (characters indexed 1, 2, and 3).

As a negative index, endSlice indicates an offset from the end of the string. string.slice(2,-1) extracts the third character through the second to last character in the string.

The following example uses slice to create a new string.

// assumes a print function is defined
var str1 = "The morning is upon us.";
var str2 = str1.slice(4, -2);
print(str2);

This writes:

morning is upon u

Available since: 4.0.0

Parameters

  • beginSlice : Number

    The zero-based index at which to begin extraction.

  • endSlice : Number

    The zero-based index at which to end extraction. If omitted, slice extracts to the end of the string.

Returns

  • String

    All characters from specified start up to (but excluding) end.

( seperator, limit ) : Array
Splits a String object into an array of strings by separating the string into substrings. ...

Splits a String object into an array of strings by separating the string into substrings.

The split method returns the new array.

When found, separator is removed from the string and the substrings are returned in an array. If separator is omitted, the array contains one element consisting of the entire string.

If separator is a regular expression that contains capturing parentheses, then each time separator is matched the results (including any undefined results) of the capturing parentheses are spliced into the output array. However, not all browsers support this capability.

Note: When the string is empty, split returns an array containing one empty string, rather than an empty array.

The following example defines a function that splits a string into an array of strings using the specified separator. After splitting the string, the function displays messages indicating the original string (before the split), the separator used, the number of elements in the array, and the individual array elements.

function splitString(stringToSplit,separator)
{
    var arrayOfStrings = stringToSplit.split(separator);
    print('The original string is: "' + stringToSplit + '"');
    print('The separator is: "' + separator + '"');
    print("The array has " + arrayOfStrings.length + " elements: ");

    for (var i=0; i < arrayOfStrings.length; i++)
        print(arrayOfStrings[i] + " / ");
}

var tempestString = "Oh brave new world that has such people in it.";
var monthString = "Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec";

var space = " ";
var comma = ",";

splitString(tempestString, space);
splitString(tempestString);
splitString(monthString, comma);

This example produces the following output:

The original string is: "Oh brave new world that has such people in it."
The separator is: " "
The array has 10 elements: Oh / brave / new / world / that / has / such / people / in / it. /

The original string is: "Oh brave new world that has such people in it."
The separator is: "undefined"
The array has 1 elements: Oh brave new world that has such people in it. /

The original string is: "Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec" The separator is: "," The array has 12 elements: Jan / Feb / Mar / Apr / May / Jun / Jul / Aug / Sep / Oct / Nov / Dec /

In the following example, split looks for 0 or more spaces followed by a semicolon followed by 0 or more spaces and, when found, removes the spaces from the string. nameList is the array returned as a result of split.

var names = "Harry Trump ;Fred Barney; Helen Rigby ; Bill Abel ;Chris Hand ";
print(names);
var re = /\s*;\s*\/;
var nameList = names.split(re);
print(nameList);

This prints two lines; the first line prints the original string, and the second line prints the resulting array.

Harry Trump ;Fred Barney; Helen Rigby ; Bill Abel ;Chris Hand
Harry Trump,Fred Barney,Helen Rigby,Bill Abel,Chris Hand

In the following example, split looks for 0 or more spaces in a string and returns the first 3 splits that it finds.

var myString = "Hello World. How are you doing?";
var splits = myString.split(" ", 3);
print(splits);

This script displays the following:

Hello,World.,How

If separator contains capturing parentheses, matched results are returned in the array.

var myString = "Hello 1 word. Sentence number 2.";
var splits = myString.split(/(\d)/);
print(splits);

This script displays the following:

Hello ,1, word. Sentence number ,2, .

Available since: 4.0.0

Parameters

  • seperator : String

    Specifies the character to use for separating the string. The separator is treated as a string or a regular expression. If separator is omitted, the array returned contains one element consisting of the entire string.

  • limit : Number

    Integer specifying a limit on the number of splits to be found. The split method still splits on every match of separator, but it truncates the returned array to at most limit elements.

Returns

  • Array

    Substrings are returned in an array.

( start, length ) : String
Returns the characters in a string beginning at the specified location through the specified number of characters. ...

Returns the characters in a string beginning at the specified location through the specified number of characters.

start is a character index. The index of the first character is 0, and the index of the last character is 1 less than the length of the string. substr begins extracting characters at start and collects length characters (unless it reaches the end of the string first, in which case it will return fewer).

If start is positive and is greater than or equal to the length of the string, substr returns an empty string.

If start is negative, substr uses it as a character index from the end of the string. If start is negative and abs(start) is larger than the length of the string, substr uses 0 as the start index. Note: the described handling of negative values of the start argument is not supported by Microsoft JScript.

If length is 0 or negative, substr returns an empty string. If length is omitted, substr extracts characters to the end of the string.

Consider the following script:

// assumes a print function is defined
var str = "abcdefghij";
print("(1,2): "    + str.substr(1,2));
print("(-3,2): "   + str.substr(-3,2));
print("(-3): "     + str.substr(-3));
print("(1): "      + str.substr(1));
print("(-20, 2): " + str.substr(-20,2));
print("(20, 2): "  + str.substr(20,2));

This script displays:

(1,2): bc
(-3,2): hi
(-3): hij
(1): bcdefghij
(-20, 2): ab
(20, 2):

Available since: 4.0.0

Parameters

  • start : Number

    Location at which to begin extracting characters.

  • length : Number

    The number of characters to extract.

Returns

( indexA, [indexB] ) : String
Returns the characters in a string between two indexes into the string. ...

Returns the characters in a string between two indexes into the string.

substring extracts characters from indexA up to but not including indexB. In particular: * If indexA equals indexB, substring returns an empty string. * If indexB is omitted, substring extracts characters to the end of the string. * If either argument is less than 0 or is NaN, it is treated as if it were 0. * If either argument is greater than stringName.length, it is treated as if it were stringName.length.

If indexA is larger than indexB, then the effect of substring is as if the two arguments were swapped; for example, str.substring(1, 0) == str.substring(0, 1).

The following example uses substring to display characters from the string "Sencha":

// assumes a print function is defined
var anyString = "Sencha";

// Displays "Sen"
print(anyString.substring(0,3));
print(anyString.substring(3,0));

// Displays "cha"
print(anyString.substring(3,6));
print(anyString.substring(6,3));

// Displays "Sencha"
print(anyString.substring(0,6));
print(anyString.substring(0,10));

The following example replaces a substring within a string. It will replace both individual characters and substrings. The function call at the end of the example changes the string "Brave New World" into "Brave New Web".

function replaceString(oldS, newS, fullS) {
    // Replaces oldS with newS in the string fullS
    for (var i = 0; i < fullS.length; i++) {
        if (fullS.substring(i, i + oldS.length) == oldS) {
            fullS = fullS.substring(0, i) + newS + fullS.substring(i + oldS.length,

fullS.length);

        }
    }
    return fullS;
}

replaceString("World", "Web", "Brave New World");

Available since: 4.0.0

Parameters

  • indexA : Number

    An integer between 0 and one less than the length of the string.

  • indexB : Number (optional)

    An integer between 0 and the length of the string.

Returns

  • String

    Returns the characters in a string between two indexes into the string.

The characters within a string are converted to lower case while respecting the current locale. ...

The characters within a string are converted to lower case while respecting the current locale. For most languages, this will return the same as toLowerCase.

The toLocaleLowerCase method returns the value of the string converted to lower case according to any locale-specific case mappings. toLocaleLowerCase does not affect the value of the string itself. In most cases, this will produce the same result as toLowerCase(), but for some locales, such as Turkish, whose case mappings do not follow the default case mappings in Unicode, there may be a different result.

The following example displays the string "sencha":

var upperText="SENCHA";
document.write(upperText.toLocaleLowerCase());

Available since: 4.0.0

Returns

  • String

    Returns value of the string in lowercase.

The characters within a string are converted to upper case while respecting the current locale. ...

The characters within a string are converted to upper case while respecting the current locale. For most languages, this will return the same as toUpperCase.

The toLocaleUpperCase method returns the value of the string converted to upper case according to any locale-specific case mappings. toLocaleUpperCase does not affect the value of the string itself. In most cases, this will produce the same result as toUpperCase(), but for some locales, such as Turkish, whose case mappings do not follow the default case mappings in Unicode, there may be a different result.

The following example displays the string "SENCHA":

var lowerText="sencha";
document.write(lowerText.toLocaleUpperCase());

Available since: 4.0.0

Returns

  • String

    Returns value of the string in uppercase.

Returns the calling string value converted to lower case. ...

Returns the calling string value converted to lower case.

The toLowerCase method returns the value of the string converted to lowercase. toLowerCase does not affect the value of the string itself.

The following example displays the lowercase string "sencha":

var upperText="SENCHA";
document.write(upperText.toLowerCase());

Available since: 4.0.0

Returns

  • String

    Returns value of the string in lowercase.

Returns a string representing the specified object. ...

Returns a string representing the specified object. Overrides the Object.toString method.

The String object overrides the toString method of the Object object; it does not inherit Object.toString. For String objects, the toString method returns a string representation of the object.

The following example displays the string value of a String object:

x = new String("Hello world");
alert(x.toString())      // Displays "Hello world"

Available since: 4.0.0

Returns

  • String

    A string representation of the object.

Returns the calling string value converted to uppercase. ...

Returns the calling string value converted to uppercase.

The toUpperCase method returns the value of the string converted to uppercase. toUpperCase does not affect the value of the string itself.

The following example displays the string "SENCHA":

var lowerText="sencha";
document.write(lowerText.toUpperCase());

Available since: 4.0.0

Returns

  • String

    Returns value of the string in uppercase.

Removes whitespace from both ends of the string. ...

Removes whitespace from both ends of the string.

Does not affect the value of the string itself.

The following example displays the lowercase string "foo":

var orig = "   foo  ";
alert(orig.trim());

NOTE: This method is part of the ECMAScript 5 standard.

Available since: 2.3.0

Returns

  • String

    A string stripped of whitespace on both ends.

Returns the primitive value of the specified object. ...

Returns the primitive value of the specified object. Overrides the Object.valueOf method.

The valueOf method of String returns the primitive value of a String object as a string data type. This value is equivalent to String.toString.

This method is usually called internally by JavaScript and not explicitly in code.

x = new String("Hello world");
alert(x.valueOf())          // Displays "Hello world"

Available since: 4.0.0

Returns

  • String

    Returns value of string.