Javascript Function Basic – Take of first part of url

var url = x;
var array = url.split('/');
thetext = array[array.length-1];
var thetextshort = thetext.substring(thetext.lastIndexOf("/") + 1, url.length);
return thetextshort;
}
alert(multiply("www.codehaven.co.uk/firstpart/secondpart/themainimage.jpg"));