JavaScript判断数组是否包含指定的元素,这段代码通过prototype定义了数组方法,这样就可以在任意数组调用contains方法
/** * 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; }
用法
// Now you can do things like: var x = Array(); if (x.contains('foo')) { // do something special }