document.onmousedown = function(){document.onmousemove = getMouseX;}; //invocation

function getMouseX(e)
{
	var IE = document.all?true:false
	if (!IE)
		document.captureEvents(Event.MOUSEMOVE);
	var tempX = 0;
		if (IE) // grab the x-y pos.s if browser is IE
	tempX = event.clientX + document.body.scrollLeft;
		else // grab the x-y pos.s if browser is NS
	tempX = e.pageX;
	// catch possible negative values in NS4
	if (tempX < 0)
		tempX = 0;
	// show the position values in the form named Show
	// in the text fields named MouseX and MouseY
	dbgField.value = tempX;
	tmpLayer.style.left = tempX;
}