How can I check if an array contains a specified item?

Question

I use jQuery for my application and I have an array which contains string items:

var array = ["item","item1","item2","item3"]

How I can test if array contains "item"?

• Jack: developer.mozilla.org/en-US/docs/JavaScript/Reference/…
• Tomas Ramirez Sarduy: Now I think is duplicated :(

Answer 1

You can use array.indexOf("item") - It returns -1 if the item is not found or the index where the item is found.

Note that this is not supported in older versions of IE.

• JeffS: Note that this uses === for comparison. MDN has a polyfill for those versions of IE here: developer.mozilla.org/en-US/docs/JavaScript/Reference/…
• dfsq: But better to use $.inArray - it will use hative Array.indexOf if available.
• techfoobar: @dfsq - Yes, better to use $.inArray as it'll work equally well on all browsers.

Answer 2

if ($.inArray("item", array) > -1)

Answer 3

Javascript

Modern browsers have Array#indexOf, which does exactly that; this is in the ECMAScript v5 edition specification, but it has been in several browsers for years. Older browsers can be supported using the code listed in the "compatibility" section at the bottom of that page.

if(array.indexOf("item") > -1){
 //doSomething
}

jQuery

jQuery has a utility function for this:

if($.inArray(value, array)){
 //doSomething
}

It returns the index of a value in an array. It returns -1 if the array does not contain the value.

Duplicated?

• Best way to find if an item is in a JavaScript array?
• How do I check if an array includes an object in JavaScript?