JavaScript 获取鼠标位置

function doSomething(e) {
    var posx = 0;
    var posy = 0;
    if (!e) var e = window.event;
    if (e.pageX || e.pageY)     {
        posx = e.pageX;
        posy = e.pageY;
    }
    else if (e.clientX || e.clientY)    {
        posx = e.clientX + document.body.scrollLeft
            + document.documentElement.scrollLeft;
        posy = e.clientY + document.body.scrollTop
            + document.documentElement.scrollTop;
    }
    // posx and posy contain the mouse position relative to the document
    // Do something with this information
}