How to check if a string "StartsWith" another string?

How would I write the equivalent of C#'s String.StartsWith in JavaScript? var haystack = 'hello world'; var needle = 'he'; haystack.startsWith(needle) == true Note: This is an old question, and as pointed out in the comments ECMAScript 2015 (ES6) introduced the .startsWith method. However, at the time of writing this update (2015) browser support is far from complete.

[nilab]

Javascript StartsWith - Stack Overflow : if(typeof String.prototype.startsWith != 'function'){String.prototype.startsWith=function(str){return this.indexOf(str)==0;};}