var wrapper = document.getElementById('wrapper'),

    box1 = document.getElementById('box1'),

    box2 = document.getElementById('box2'),

    box3 = document.getElementById('box3'),

    result = document.getElementById('result'),

    x, y, w;

​

function doCoords (el) {

  'use strict';

  x = el.getBoundingClientRect().left;

  y = el.getBoundingClientRect().top;

  if (el.getBoundingClientRect().width) {

    w = el.getBoundingClientRect().width; // for modern browsers

  } else {

    w = el.offsetWidth; // for oldIE

  }

  return x + "px from the left,<br>" + y + "px from the top,<br>" + w + "px width.";

}

​

function doResult (el) {

  'use strict';

  result.innerHTML = doCoords(el);

  // resize the window to see the coordinates change on the fly

  window.onresize = function () {

    doResult(el);

  };

​

}

​

// change the parameter to wrapper, box1, box2, or box3

doResult(wrapper);