strRightBack in javascript

The following is a function equivalent to lotus script's strRightBack function.

Code
 function strRightBack(stringValue,seperator)    {
    var pos=stringValue.lastIndexOf(seperator);
    var result=stringValue.substring(pos+1,stringValue.length)
    return result;
}

Illustriation
var x="My Name~ My Friend Name";
alert(strRightBack(x,"~"));    // this will alert " My Friend Name"

Following is a code that will help you extend native javascript's String class with this function

Code
String.prototype.strRightBack=function(seperator)    {
    //stringValue
    var pos=this.lastIndexOf(seperator);
    var result=this.substring(pos+1,this.length)
    return result;
}

Illustriation
var x="My Name~ My Friend Name";
alert(x.strRightBack("~"));    // this will alert " My Friend Name"