Cross browser caretRangeFromPoint

caretRangeFromPoint.js

//demo: http://jsfiddle.net/heZ4z/

if (document.addEventListener) { // standard

  document.addEventListener('click', function onclick(e) {
    var r;
    if (document.caretRangeFromPoint) { // standard (WebKit)
      r = document.caretRangeFromPoint(e.pageX, e.pageY);
    } else if (e.rangeParent) { // Mozilla
      r = document.createRange();
      r.setStart(e.rangeParent, e.rangeOffset);
    }

    var t = r.startContainer; // should be a text node
    var s = r.startOffset; // number of chars from the start of text
    var e = s;

    while (s > 0) {
      s -= 1;
      r.setStart(t, s);
      if (/^\s/.test(r.toString())) {
        r.setStart(t, s += 1);
        break;
      }
    }
    var l = t.nodeValue.length;
    while (e < l) {
      e += 1;
      r.setEnd(t, e);
      if (/\s$/.test(r.toString())) {
        r.setEnd(t, e -= 1);
        break;
      }
    }

    window.getSelection().addRange(r);
    alert(r.toString());

  }, false);

} else if (document.attachEvent) { // IE

  document.attachEvent('onclick', function onclick(e) {
    if (!e) e = window.event;
    if (document.selection && document.selection.createRange) {
      var r = document.selection.createRange();
      r.moveToPoint(e.x, e.y);

      r.moveStart('word', -1);
      if (/^\s/.test(r.text)) r.moveStart('character', 1);
      r.moveEnd('word', 1);
      if (/\s$/.test(r.text)) r.moveEnd('character', -1);

      r.select();

      alert(r.text);
    }
  });

}