javascript获取鼠标位置部分的实例代码(兼容IE,FF)

var xPos; 
var yPos; 
document.onmousemove = mouseMove; 
function mouseMove(ev) { 
ev = ev window.event; 
var mousePos = mouseCoords(ev); 
xPos = mousePos.x; 
yPos = mousePos.y; 
} 
function mouseCoords(ev) { 
if (ev.pageX ev.pageY) { 
return { x: ev.pageX, y: ev.pageY }; 
} 
return { 
x:ev.clientX+document.body.scrollLeft+document.documentElement.scrollLeft, 
y:ev.clientY + document.body.scrollTop + document.documentElement.scrollTop 
}; 
}