prototype - load javascript

function addScript(url) {
    var script = document.createElement('script');
    script.src = url;
    document.getElementsByTagName('head')[0].appendChild(script);
}


or 


function AttachScript(src)
{
    var script = document.createElement('script');
    script.type = 'text/javascript';
    document.getElementsByTagName('body')[0].appendChild(script);
    script.src = src;
}