String Object (JavaScript)

Allows manipulation and formatting of text strings and determination and location of substrings within strings.

Syntax


newString = new String(["stringLiteral"])  

Parameters

newString
Required. The variable name to which the String object is assigned.

stringLiteral
Optional. Any group of Unicode characters.

Remarks

JavaScript provides escape sequences that you can include in strings to create characters that you cannot type directly. For example, \t specifies a tab character. For more information, see Special Characters.

String Literals

A string literal is zero or more characters enclosed in single or double quotation marks. A string literal has a primary (primitive) data type of string. A String object is created by using the new Operator, and has a data type of Object.

The following example shows that the data type of a string literal is not the same as that of a String object.

var strLit = "This is a string literal.";  
var strObj = new String("This is a string object.");  

document.write(typeof strLit);  
document.write("<br/>");  
document.write(typeof strObj);  
// Output:  
// string  
// object  

Methods for String Literals

When you call a method on a string literal, it is temporarily converted to a string wrapper object. The string literal is treated as though the new operator were used to create it.

The following example applies the toUpperCase method to a string literal.

var strLit = "This is a string literal.";  

var result1 = strLit.toUpperCase();  

var result2 = (new String(strLit)).toUpperCase();  

document.write(result1);  
document.write("<br/>");  
document.write(result2);  
// Output:   
// THIS IS A STRING LITERAL.  
// THIS IS A STRING LITERAL.  

Accessing an Individual Character

You can access an individual character of a string as a read-only array-indexed property. This feature was introduced in Internet Explorer 9 standards mode, Internet Explorer 10 standards mode, Internet Explorer 11 standards mode, and Windows Store apps. The following example accesses individual string characters.

var str = "abcd";  
var result = str[2];  
document.write (result);  
// Output: c  

var result = "the"[0];  
document.write(result);  
// Output: t  

Requirements

The String Object was introduced in Internet Explorer before Internet Explorer 6. Some members in the following lists were introduced in later versions.

Properties

The following table lists the properties of the String object.

Property Description
constructor Property Specifies the function that creates an object.
length Property (String) Returns the length of a String object.
prototype Property Returns a reference to the prototype for a class of objects.

Functions

The following table lists the functions of the String object.

Function Description
String.fromCharCode Function Returns a string from a number of Unicode character values.
String.fromCodePoint Function Returns the string associated with a Unicode UTF-16 code point.
String.raw Function Returns the raw string form of a template string.

Methods

The following table lists the methods of the String object.

Method Description
anchor Method Places an HTML anchor that has a NAME attribute around text.
big Method Places HTML <BIG> tags around text.
blink Method Places HTML <BLINK> tags around text.
bold Method Places HTML <B> tags around text.
charAt Method Returns the character at the specified index.
charCodeAt Method Returns the Unicode encoding of the specified character.
codePointAt Method Returns the code point for a Unicode UTF-16 character.
concat Method (String) Returns a string that contains the concatenation of two supplied strings.
endsWith Method Returns a Boolean value that indicates whether a string or substring ends with the passed in string.
includes Method Returns a Boolean value that indicates whether the passed in string is contained in the string object.
fixed Method Places HTML <TT> tags around text.
fontcolor Method Places HTML <FONT> tags with a COLOR attribute around text.
fontsize Method Places HTML <FONT> tags with a SIZE attribute around text.
hasOwnProperty Method Returns a Boolean value that indicates whether an object has a property with the specified name.
indexOf Method (String) Returns the character position where the first occurrence of a substring occurs within a string.
isPrototypeOf Method Returns a Boolean value that indicates whether an object exists in another object's prototype chain.
italics Method Places HTML <I> tags around text.
lastIndexOf Method (String) Returns the last occurrence of a substring within a string.
link Method Places an HTML anchor that has an HREF attribute around text.
localeCompare Method Returns a value that indicates whether two strings are equivalent in the current locale.
match Method Searches a string by using a supplied Regular Expression object and returns the results as an array.
normalize Method Returns the Unicode Normalization Form of a specified string.
propertyIsEnumerable Method Returns a Boolean value that indicates whether a specified property is part of an object and whether it is enumerable.
repeat Method Returns a new string object with a value equal to the original string repeated the specified number of times.
replace Method Uses a regular expression to replace text in a string and returns the result.
search Method Returns the position of the first substring match in a regular expression search.
slice Method (String) Returns a section of a string.
small Method Places HTML <SMALL> tags around text.
split Method Returns the array of strings that results when a string is separated into substrings.
startsWith Method Returns a Boolean value that indicates whether a string or substring starts with the passed in string.
strike Method Places HTML <STRIKE> tags around text.
sub Method Places HTML <SUB> tags around text.
substr Method Returns a substring beginning at a specified location and having a specified length.
substring Method Returns the substring at a specified location within a String object.
sup Method Places HTML <SUP> tags around text.
toLocaleLowerCase Method Returns a string in which all alphabetic characters are converted to lowercase, taking into account the host environment's current locale.
toLocaleString Method Returns an object converted to a string, using the current locale.
toLocaleUpperCase Method Returns a string in which all alphabetic characters are converted to uppercase, taking into account the host environment's current locale.
toLowerCase Method Returns a string in which all alphabetic characters are converted to lowercase.
toString Method Returns the string.
toUpperCase Method Returns a string in which all alphabetic characters are converted to uppercase.
trim Method Returns a string with leading and trailing white space and line terminator characters removed.
valueOf Method Returns the string.

See Also

new Operator
Scrolling, panning, and zooming sample app