JavaScript method for determining whether an array contains a specified element _ javascript tips-js tutorial

This article describes how to use JavaScript to determine whether an array contains a specified Element and how to use the contains method in javascript, for more information about how to use JavaScript to determine whether an array contains a specified element, see the following example. Share it with you for your reference. The details are as follows:

This Code defines the array method through prototype, so that the contains method can be called in any array.

/*** Array. prototype. [method name] allows you to define/overwrite an objects method * needle is the item you are searching for * this is a special variable that refers to "this" instance of an Array. * returns true if needle is in the array, and false otherwise */Array. prototype. contains = function (needle) {for (I in this) {if (this [I] = needle) return true;} return false ;}

Usage:

// Now you can do things like: var x = Array (); if (x. contains ('foo') {// do something special}

I hope this article will help you design javascript programs.