xpath experiment

replaceJquery.js

this.replaceURL = function(old, newurl) {
    var x = document.evaluate('//script[@type="text/javascript" and @src="'+old+'"]', document, null, XPathResult.UNORDERED_NODE_ITERATOR_TYPE, null);
    var oldScript = x.iterateNext();
    if (!oldScript)
        return;
    oldScript.src = newurl;
    console.log(oldScript);
};

replaceURL("http://ajax.googleapis.com/ajax/libs/jquery/1.5.2/jquery.min.js", "http://ajax.googleapis.com/ajax/libs/mootools/1.3.2/mootools-yui-compressed.js");