var mouseX=0, mouseY=0;

document.onmousemove = getMousePosition;

function getMousePosition(e) {
	try {
		if (!e) e = window.event;
		if (e.pageX)
			mouseX = e.pageX;
		else if (e.clientX)
			mouseX = e.clientX + (document.documentElement.scrollLeft ? document.documentElement.scrollLeft : document.body.scrollLeft);
		else
			mouseX = null;

		if (e.pageY)
			mouseY = e.pageY;
		else if (e.clientY)
			mouseY = e.clientY + (document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop);
		else
			mouseY = null;
	} catch(e) {
		// This is here so that the page doesn't throw errors when there is no
		// document.  That seems to happen in IE when the mouse is moving while the
		// page is loading.
	}
}
//使用时要??mouseX +'px'