[Scott MacVicar]

Basically you'll find 3 functions needed for ajax compatibility.
// create the vb ajax object, the parameter is if its to be asynchronous or not
var xml_sender = new vB_AJAX_Handler(true);
// function to be called when ready state changes
xml_sender.onreadystatechange(myfunction);
// send the request
xml_sender.send('file.php', 'do=something&var=' + blahvar);

so when it changes myfunction will be executed.