JavaScript ：获取元素的坐标的三种方法

这是从别人那里看到的方法，具体出处不记得了，做下记录。

//获取div的坐标
//方法一
function check() {
    var obj = document.getElementById('deleteDiv')
    //方法一
    var x = obj.getBoundingClientRect().left;

    var y = obj.getBoundingClientRect().top;

    alert("方法一:" + x + "," + y);

    //方法二


    alert("方法二:" + GetObjPos(obj)['x'] + "," + GetObjPos(obj)['y']); //x坐标

    var xd = getElementPos("deleteDiv");
    alert("方法三:" + xd.x+"," + xd.y);

}
//方法二

function CPos(x, y) {
    this.x = x;
    this.y = y;
}
/**
* 得到对象的相对浏览器的坐标        
*/
function GetObjPos(ATarget) {

    var target = ATarget;

    var pos = new CPos(target.offsetLeft, target.offsetTop);

    var target = target.offsetParent;

    while (target) {
        pos.x += target.offsetLeft;
        pos.y += target.offsetTop;
        target = target.offsetParent
    }
    return pos;
}



//方法三
function getElementPos(elementId) {
    var ua = navigator.userAgent.toLowerCase();
    var isOpera = (ua.indexOf('opera') != -1);
    var isIE = (ua.indexOf('msie') != -1 && !isOpera); // not opera spoof 
    var el = document.getElementById(elementId);
    if (el.parentNode === null || el.style.display == 'none') {
        return false;
    }
    var parent = null;
    var pos = [];
    var box;

    if (el.getBoundingClientRect) //IE    
    {
        box = el.getBoundingClientRect();

        var scrollTop = Math.max(document.documentElement.scrollTop, document.body.scrollTop);

        var scrollLeft = Math.max(document.documentElement.scrollLeft, document.body.scrollLeft);

        return {
            x: box.left + scrollLeft,
            y: box.top + scrollTop
        };
    }
    else

        if (document.getBoxObjectFor) // gecko        
        {
            box = document.getBoxObjectFor(el);

            var borderLeft = (el.style.borderLeftWidth) ? parseInt(el.style.borderLeftWidth) : 0;
            var borderTop = (el.style.borderTopWidth) ? parseInt(el.style.borderTopWidth) : 0;

            pos = [box.x - borderLeft, box.y - borderTop];
        }
        else // safari & opera        
        {
            pos = [el.offsetLeft, el.offsetTop];
            parent = el.offsetParent;
            if (parent != el) {
                while (parent) {
                    pos[0] += parent.offsetLeft;
                    pos[1] += parent.offsetTop;
                    parent = parent.offsetParent;
                }
            }
            if (ua.indexOf('opera') != -1 || (ua.indexOf('safari') != -1 && el.style.position == 'absolute')) {
                pos[0] -= document.body.offsetLeft;
                pos[1] -= document.body.offsetTop;
            }
        }

    if (el.parentNode) {
        parent = el.parentNode;

    }
    else {
        parent = null;
    }

    while (parent && parent.tagName != 'BODY' && parent.tagName != 'HTML') { // account for any scrolled       ancestors

        pos[0] -= parent.scrollLeft;
        pos[1] -= parent.scrollTop;
        if (parent.parentNode) {
            parent = parent.parentNode;
        }
        else {
            parent = null;
        }
    }
    return {
        x: pos[0],
        y: pos[1]
    };
}

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