Find X/Y of an HTML element with JavaScript [duplicate]

Question

Here's how I do it:

// Based on: http://www.quirksmode.org/js/findpos.html
var getCumulativeOffset = function (obj) {
    var left, top;
    left = top = 0;
    if (obj.offsetParent) {
        do {
            left += obj.offsetLeft;
            top  += obj.offsetTop;
        } while (obj = obj.offsetParent);
    }
    return {
        x : left,
        y : top
    };
};

That can be tricky depending on browser and version. I would suggest using jQuery and the positions plugin.

You can use a library such as Prototype or jQuery, or you can use this handy function:

It returns an array.

myPos = findPos(document.getElementById('something'))
x = myPos[0]
y = myPos[1]

function findPos(obj) {
  var curleft = curtop = 0;
  if (obj.offsetParent) {
    curleft = obj.offsetLeft
    curtop = obj.offsetTop
    while (obj = obj.offsetParent) {
      curleft += obj.offsetLeft
      curtop += obj.offsetTop
    }
  }
  return [curleft,curtop];
}

For what it's worth, here's a recursive version:

function findPos(element) {
  if (element) {
    var parentPos = findPos(element.offsetParent);
    return [
      parentPos.X + element.offsetLeft,
      parentPos.Y + element.offsetTop
    ];
  } else {
    return [0,0];
  }
}

You can add two properties to the Element.prototype to get top/left of any element.

window.Object.defineProperty( Element.prototype, 'documentOffsetTop', {
    get: function () { return this.offsetTop + ( this.offsetParent ? this.offsetParent.documentOffsetTop : 0 ); }
} );

window.Object.defineProperty( Element.prototype, 'documentOffsetLeft', {
    get: function () { return this.offsetLeft + ( this.offsetParent ? this.offsetParent.documentOffsetLeft : 0 ); }
} );

Here's a demo comparing the results to jQuery's offset().top and .left: http://jsfiddle.net/ThinkingStiff/3G7EZ/