String.prototype

The String.prototype property represents the String prototype object.

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.matchAll()

Returns an iterator of all matches.

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()

<b>

String.prototype.fixed()

<tt>

String.prototype.fontcolor()

<font color="color">

String.prototype.fontsize()

<font size="size">

String.prototype.italics()

<i>

String.prototype.link()

<a href="url"> (link to URL)

String.prototype.small()

<small>

String.prototype.strike()

<strike>

String.prototype.sub()

<sub>

String.prototype.sup()

<sup>

Specifications

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

See also

• String
• Function.prototype