// try replacing _= if it is there
var ret = s.url.replace(/(\?|&)_=.*?(&|$)/, "$1_=" + ts + "$2");
// if nothing was replaced, add timestamp to the end
// try replacing _= if it is there
var ret = s.url.replace(/(\?|&)_=.*?(&|$)/, "$1_=" + ts + "$2");
// if nothing was replaced, add timestamp to the end