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String.prototype

The String.prototype property represents the String prototype object.

Property attributes of `String.prototype`
Writable	no
Enumerable	no
Configurable	no

Description

All String instances inherit from String.prototype. Changes to the String prototype object are propagated to all String instances.

Properties

String.prototype.constructor: Specifies the function that creates an object's prototype.
String.prototype.length: Reflects the length of the string.
N: Used to access the character in the Nth position where N is an integer between 0 and one less than the value of length. These properties are read-only.

Methods

Methods unrelated to HTML

String.prototype.charAt(): Returns the character (exactly one UTF-16 code unit) at the specified index.
String.prototype.charCodeAt(): Returns a number that is the UTF-16 code unit value at the given index.
String.prototype.codePointAt(): Returns a nonnegative integer Number that is the code point value of the UTF-16 encoded code point starting at the specified index.
String.prototype.concat(): Combines the text of two strings and returns a new string.
String.prototype.includes(): Determines whether one string may be found within another string.
String.prototype.endsWith(): Determines whether a string ends with the characters of another string.
String.prototype.indexOf(): Returns the index within the calling String object of the first occurrence of the specified value, or -1 if not found.
String.prototype.lastIndexOf(): Returns the index within the calling String object of the last occurrence of the specified value, or -1 if not found.
String.prototype.localeCompare(): Returns a number indicating whether a reference string comes before or after or is the same as the given string in sort order.
String.prototype.match(): Used to match a regular expression against a string.
String.prototype.normalize(): Returns the Unicode Normalization Form of the calling string value.
String.prototype.padEnd(): Pads the current string from the end with a given string to create a new string from a given length.
String.prototype.padStart(): Pads the current string from the start with a given string to create a new string from a given length.
~~String.prototype.quote()~~: ~~Wraps the string in double quotes (""").~~
String.prototype.repeat(): Returns a string consisting of the elements of the object repeated the given times.
String.prototype.replace(): Used to find a match between a regular expression and a string, and to replace the matched substring with a new substring.
String.prototype.search(): Executes the search for a match between a regular expression and a specified string.
String.prototype.slice(): Extracts a section of a string and returns a new string.
String.prototype.split(): Splits a String object into an array of strings by separating the string into substrings.
String.prototype.startsWith(): Determines whether a string begins with the characters of another string.
String.prototype.substr(): Returns the characters in a string beginning at the specified location through the specified number of characters.
String.prototype.substring(): Returns the characters in a string between two indexes into the string.
String.prototype.toLocaleLowerCase(): 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().
String.prototype.toLocaleUpperCase(): 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().
String.prototype.toLowerCase(): Returns the calling string value converted to lower case.
String.prototype.toSource(): Returns an object literal representing the specified object; you can use this value to create a new object. Overrides the Object.prototype.toSource() method.
String.prototype.toString(): Returns a string representing the specified object. Overrides the Object.prototype.toString() method.
String.prototype.toUpperCase(): Returns the calling string value converted to uppercase.
String.prototype.trim(): Trims whitespace from the beginning and end of the string. Part of the ECMAScript 5 standard.
String.prototype.trimStart() String.prototype.trimLeft(): Trims whitespace from the beginning of the string.
String.prototype.trimEnd() String.prototype.trimRight(): Trims whitespace from the end of the string.
String.prototype.valueOf(): Returns the primitive value of the specified object. Overrides the Object.prototype.valueOf() method.
String.prototype[@@iterator](): Returns a new Iterator object that iterates over the code points of a String value, returning each code point as a String value.

HTML wrapper methods

These methods are of limited use, as they provide only a subset of the available HTML tags and attributes.

String.prototype.anchor(): <a name="name"> (hypertext target)
String.prototype.big(): <big>
String.prototype.blink(): <blink>
String.prototype.bold(): 
String.prototype.fixed(): <tt>
String.prototype.fontcolor(): 
String.prototype.fontsize(): 
String.prototype.italics(): 
String.prototype.link(): <a href="url"> (link to URL)
String.prototype.small(): 
String.prototype.strike(): <strike>
String.prototype.sub(): 
String.prototype.sup():

Specifications

Specification	Status	Comment
ECMAScript 1st Edition (ECMA-262)	Standard	Initial definition.
ECMAScript 5.1 (ECMA-262) The definition of 'String.prototype' in that specification.	Standard
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'String.prototype' in that specification.	Standard
ECMAScript Latest Draft (ECMA-262) The definition of 'String.prototype' in that specification.	Draft

Browser compatibilityUpdate compatibility data on GitHub

	Desktop
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari
Basic support	Yes	Yes	1	Yes	Yes	Yes

	Mobile
	Android webview	Chrome for Android	Edge Mobile	Firefox for Android	Opera for Android	iOS Safari	Samsung Internet
Basic support	Yes	Yes	Yes	4	Yes	Yes	Yes

	Server
	Node.js
Basic support	Yes