JavaScript判断数组是否包含指定元素的方法

/** * 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;}

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