As said in this post http://rickyrosario.com/blog/javascript-startswith-and-endswith-implementation-for-strings/

var str = To be, or not to be, that is the question.;

function strEndsWith(str, suffix) {

    return str.match(suffix+$)==suffix;

}

alert(strEndsWith(str,question.));

this will return true if it ends with provided suffix.

JSFIDDLE

EDIT

There is a similar question asked before check it here

the answer says

var str = To be, or not to be, that is the question$;

String.prototype.endsWith = function(suffix) {

    return this.indexOf(suffix, this.length - suffix.length) !== -1;

};

alert(str.endsWith($));