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JS Tutorial

JS HOME JS Introduction JS Where To JS Output JS Statements JS Syntax JS Comments JS Variables JS Let JS Const JS Operators JS Arithmetic JS Assignment JS Data Types JS Functions JS Objects JS Object Properties JS Object Methods JS Object Display JS Object Constructors JS Events JS Strings JS String Methods JS String Search JS String Templates JS Numbers JS BigInt JS Number Methods JS Number Properties JS Arrays JS Array Methods JS Array Search JS Array Sort JS Array Iteration JS Array Const JS Dates JS Date Formats JS Date Get Methods JS Date Set Methods JS Math JS Random JS Booleans JS Comparisons JS If Else JS Switch JS Loop For JS Loop For In JS Loop For Of JS Loop While JS Break JS Iterables JS Sets JS Set Methods JS Maps JS Map Methods JS Typeof JS Type Conversion JS Destructuring JS Bitwise JS RegExp JS Precedence JS Errors JS Scope JS Hoisting JS Strict Mode JS this Keyword JS Arrow Function JS Classes JS Modules JS JSON JS Debugging JS Style Guide JS Best Practices JS Mistakes JS Performance JS Reserved Words

JS Versions

JS Versions JS 2009 (ES5) JS 2015 (ES6) JS 2016 JS 2017 JS 2018 JS 2019 JS 2020 JS 2021 JS 2022 JS 2023 JS 2024 JS IE / Edge JS History

JS Objects

Object Definitions Object Prototypes Object Methods Object Properties Object Get / Set Object Protection

JS Functions

Function Definitions Function Parameters Function Invocation Function Call Function Apply Function Bind Function Closures

JS Classes

Class Intro Class Inheritance Class Static

JS Async

JS Callbacks JS Asynchronous JS Promises JS Async/Await

JS HTML DOM

DOM Intro DOM Methods DOM Document DOM Elements DOM HTML DOM Forms DOM CSS DOM Animations DOM Events DOM Event Listener DOM Navigation DOM Nodes DOM Collections DOM Node Lists

JS Browser BOM

JS Window JS Screen JS Location JS History JS Navigator JS Popup Alert JS Timing JS Cookies

JS Web APIs

Web API Intro Web Forms API Web History API Web Storage API Web Worker API Web Fetch API Web Geolocation API

JS AJAX

AJAX Intro AJAX XMLHttp AJAX Request AJAX Response AJAX XML File AJAX PHP AJAX ASP AJAX Database AJAX Applications AJAX Examples

JS JSON

JSON Intro JSON Syntax JSON vs XML JSON Data Types JSON Parse JSON Stringify JSON Objects JSON Arrays JSON Server JSON PHP JSON HTML JSON JSONP

JS vs jQuery

jQuery Selectors jQuery HTML jQuery CSS jQuery DOM

JS Graphics

JS Graphics JS Canvas JS Plotly JS Chart.js JS Google Chart JS D3.js

JS Examples

JS Examples JS HTML DOM JS HTML Input JS HTML Objects JS HTML Events JS Browser JS Editor JS Exercises JS Quiz JS Website JS Interview Prep JS Bootcamp JS Certificate

JS References

JavaScript Objects HTML DOM Objects


JavaScript String Search

JavaScript String indexOf()

The indexOf() method returns the index (position) of the first occurrence of a string in a string, or it returns -1 if the string is not found:

Example

let text = "Please locate where 'locate' occurs!";
let index = text.indexOf("locate");
Try it Yourself »

Note

JavaScript counts positions from zero.

0 is the first position in a string, 1 is the second, 2 is the third, ...


JavaScript String lastIndexOf()

The lastIndexOf() method returns the index of the last occurrence of a specified text in a string:

Example

let text = "Please locate where 'locate' occurs!";
let index = text.lastIndexOf("locate");
Try it Yourself »

Both indexOf(), and lastIndexOf() return -1 if the text is not found:

Example

let text = "Please locate where 'locate' occurs!";
let index = text.lastIndexOf("John");
Try it Yourself »

Both methods accept a second parameter as the starting position for the search:

Example

let text = "Please locate where 'locate' occurs!";
let index = text.indexOf("locate", 15);
Try it Yourself »

The lastIndexOf() methods searches backwards (from the end to the beginning), meaning: if the second parameter is 15, the search starts at position 15, and searches to the beginning of the string.

Example

let text = "Please locate where 'locate' occurs!";
text.lastIndexOf("locate", 15);
Try it Yourself »

JavaScript String search()

The search() method searches a string for a string (or a regular expression) and returns the position of the match:

Examples

let text = "Please locate where 'locate' occurs!";
text.search("locate");
Try it Yourself »
let text = "Please locate where 'locate' occurs!";
text.search(/locate/);
Try it Yourself »

Did You Notice?

The two methods, indexOf() and search(), are equal?

They accept the same arguments (parameters), and return the same value?

The two methods are NOT equal. These are the differences:

  • The search() method cannot take a second start position argument.
  • The indexOf() method cannot take powerful search values (regular expressions).

You will learn more about regular expressions in a later chapter.



JavaScript String match()

The match() method returns an array containing the results of matching a string against a string (or a regular expression).

Examples

Perform a search for "ain":

let text = "The rain in SPAIN stays mainly in the plain";
text.match("ain");
Try it Yourself »

Perform a search for "ain":

let text = "The rain in SPAIN stays mainly in the plain";
text.match(/ain/);
Try it Yourself »

Perform a global search for "ain":

let text = "The rain in SPAIN stays mainly in the plain";
text.match(/ain/g);
Try it Yourself »

Perform a global, case-insensitive search for "ain":

let text = "The rain in SPAIN stays mainly in the plain";
text.match(/ain/gi);
Try it Yourself »

Note

If a regular expression does not include the g modifier (global search), match() will return only the first match in the string.

Read more about regular expressions in the chapter JS RegExp.


JavaScript String matchAll()

The matchAll() method returns an iterator containing the results of matching a string against a string (or a regular expression).

Example

const iterator = text.matchAll("Cats");
Try it Yourself »

If the parameter is a regular expression, the global flag (g) must be set, otherwise a TypeError is thrown.

Example

const iterator = text.matchAll(/Cats/g);
Try it Yourself »

If you want to search case insensitive, the insensitive flag (i) must be set:

Example

const iterator = text.matchAll(/Cats/gi);
Try it Yourself »

Notes

matchAll() is an ES2020 feature.

matchAll() does not work in Internet Explorer.


JavaScript String includes()

The includes() method returns true if a string contains a specified value.

Otherwise it returns false.

Examples

Check if a string includes "world":

let text = "Hello world, welcome to the universe.";
text.includes("world");
Try it Yourself »

Check if a string includes "world". Start at position 12:

let text = "Hello world, welcome to the universe.";
text.includes("world", 12);
Try it Yourself »

Notes

includes() is case sensitive.

includes() is an ES6 feature.

includes() is not supported in Internet Explorer.


JavaScript String startsWith()

The startsWith() method returns true if a string begins with a specified value.

Otherwise it returns false:

Examples

Returns true:

let text = "Hello world, welcome to the universe.";
text.startsWith("Hello");
Try it Yourself »

Returns false:

let text = "Hello world, welcome to the universe.";
text.startsWith("world")
Try it Yourself »

A start position for the search can be specified:

Returns false:

let text = "Hello world, welcome to the universe.";
text.startsWith("world", 5)
Try it Yourself »

Returns true:

let text = "Hello world, welcome to the universe.";
text.startsWith("world", 6)
Try it Yourself »

Notes

startsWith() is case sensitive.

startsWith() is an ES6 feature.

startsWith() is not supported in Internet Explorer.


JavaScript String endsWith()

The endsWith() method returns true if a string ends with a specified value.

Otherwise it returns false:

Examples

Check if a string ends with "Doe":

let text = "John Doe";
text.endsWith("Doe");
Try it Yourself »

Check if the 11 first characters of a string ends with "world":

let text = "Hello world, welcome to the universe.";
text.endsWith("world", 11);

Try it Yourself »

Notes

endsWith() is case sensitive.

endsWith() is an ES6 feature.

endsWith() is not supported in Internet Explorer.


Complete String Reference

For a complete String reference, go to our:

Complete JavaScript String Reference.

The reference contains descriptions and examples of all string properties and methods.

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