I am using this function:
$(\"#tooltip\").animate({ left: event.clientX, top: event.clientY });
Its working on Chrome and IE but in Firefox
You appear to be trying to use the odd global event object that is a legacy of the 4.0-browser-era Microsoft event model. Don't. Use the standard event object instead. It will be the first argument to your event handler function.
jQuery('selector').on('click', function (evt) {
jQuery("#tooltip").animate({ left: evt.clientX, top: evt.clientY });
});