//during the init we enable mouse movement event capture with this function
function save_mouse_coords(e) {
	if (document.layers){
		mouse_x = e.x;
		mouse_y = e.y;
	} else if (document.all){
		mouse_x = event.clientX;
		mouse_y = event.clientY;
	} else if (document.getElementById){
		mouse_x = e.clientX;
		mouse_y = e.clientY;
	}
	// ns4 coordinates are relative to the topmost layer the mouse is over.
	// since we are only interested in the center content column, we add its coordinates to the mouse coords for ns4
	if (ns4) {
		mouse_x = mouse_x + mouse_offset_x;
		mouse_y = mouse_y + mouse_offset_y;
	}
	if (ns6) {
		mouse_y = mouse_y + window.pageYOffset;
	}
	if (ie4) {
		mouse_y = mouse_y + document.body.scrollTop;
	}
}