How do I check if an array includes a value in JavaScript?

What is the most concise and efficient way to find out if a JavaScript array contains a value? This is the only way I know to do it: function contains(a, obj) { for (var i = 0; i < a.length; i++) { if (a[i] === obj) { return true; } } return false; } Is there a better and more concise way to accomplish this? This is very closely related to Stack Overflow question Best way to find an item in a Java

[machupicchubeta]

jquery collections contains $.inArray(value, array)

[yamadar]

array.unique, array.normarize, みたいなの。jQuery.unique(array)。ポイントは === 。