Java Enterprise Turbine
JSES - JavaScript Event Sheets
To activate the JSES functionality you just have to put in the following:
    <@jet.linkrel_es url="<your test file>"/>
in your test file you can define the javascript events like css:
.img { 
    background-color: red; onmouseover: alertImage;
You can define the function alerImage directly in your site or in a js file:
function alertImage(e){
    alert('Mouse moved over an image!' + e);