Javascript Extension Method how do I make one??

How do I make my own custom extention method like .replace("-","");

so for example:




function removeEs(text){

return text.replace("e","");
}


var s ="hello world";

var d = s.removeEs();

//d is now "hllo world"

Thanks

String.prototype.removeEs = function (){

return this.replace("e","");
}


var s ="hello world";

alert(s.removeEs());


http://www.w3schools.com/jsref/jsref_prototype_string.asp