Document doc = Document.get();
HeadElement head = (HeadElement) doc.getElementsByTagName("head").getItem(0);
if (head == null)
{
head = doc.createHeadElement();
doc.insertBefore(head, doc.getBody());
}
ScriptElement script = doc.createScriptElement(
source);
script.setType("text/javascript");
head.appendChild(script);