fiblog

javascript的犀牛书看了两边居然没有发现，还是因为我看的第四版低了。
先用document.getElementById()获取元素，然后传入下面的函数
// Get the X coordinate of the element e.
function getX(e) {
    var x = 0;                // Start with 0
    while(e) {                // Start at element e
        x += e.offsetLeft;    // Add in the offset
        e = e.offsetParent;   // And move up to the offsetParent
    }
    return x;                 // Return the total offsetLeft
}



function getY(element) {
    var y = 0;
    for(var e = element; e; e = e.offsetParent) // Iterate the offsetParents
        y += e.offsetTop;                       // Add up offsetTop values

    // Now loop up through the ancestors of the element, looking for
    // any that have scrollTop set. Subtract these scrolling values from
    // the total offset. However, we must be sure to stop the loop before
    // we reach document.body, or we'll take document scrolling into account
    // and end up converting our offset to window coordinates.
    for(e = element.parentNode; e && e != document.body; e = e.parentNode)
        if (e.scrollTop) y -= e.scrollTop;  // subtract scrollbar values

    // This is the Y coordinate with document-internal scrolling accounted for.
    return y;
}