caret.js

function caretInception( node, index, found ){
  var response = {
    found : found,
    index : index
  };

  if ( found ) {
    return response;
  }

  // if textNode - do magic
  if ( node.nodeType === 3 ) {
    if ( node.textContent.length >= index ) {
      response.found = node;
    } else {
      response.index -= node.textContent.length;
    }
    return response;
  }

  // if not textNode - make childNodes do the magic for you
  var child_response;

  $.each( node.childNodes, function( child_node_index, child_node ){
    if ( ! response.found ){
      child_response = caretInception( child_node, response.index );
      response.index = child_response.index;
      if ( child_response.found ) {
        response = child_response;
      }
    }
  });

  return response;
}

function setCaret( el, index ){
  if ( window.getSelection ){
    var sel = window.getSelection();
    sel.removeAllRanges();

    var range = document.createRange();
    range.selectNodeContents( el );

    // http://inception.davepedu.com
    var brrrrrrraaaaawwwwrwrrrmrmrmmrmrmmmmm = caretInception( el, index );

    range.setStart( brrrrrrraaaaawwwwrwrrrmrmrmmrmrmmmmm.found , brrrrrrraaaaawwwwrwrrrmrmrmmrmrmmmmm.index );
    range.collapse( true );
    sel.addRange( range );
  }
}

function getCaret( el ){
  var pos = 0;
  if ( window.getSelection ){
    if ( ! window.getSelection().rangeCount ){
      return $( el ).text().length;
    }
    var range         = window.getSelection().getRangeAt( 0 );
    var preCaretRange = range.cloneRange();

    preCaretRange.selectNodeContents( el );
    preCaretRange.setEnd( range.endContainer, range.endOffset );
    pos = preCaretRange.toString().length;
  }
  return pos;
}

function getCaretPosition( el, offset_top ){
  var range = window.getSelection().getRangeAt( 0 );
  var node  = document.createElement( 'b' );
  range.insertNode( node );

  var $node = $( node );
  var pos   = $node.position();

  if ( offset_top ){
    pos.top += $node.height();
  }
  $node.remove();

  return pos;
}