Inserts node at selection (Gecko)

insertNodeAtSelection.js

insertNodeAtSelection : function(win, insertNode, _container, _pos)
{
    // get current selection
    var sel = this._getSelection(); var doc = this._getDoc();

    // get the first range of the selection (there's almost always only
    // one range)
    var range = sel.getRangeAt(0);

    // deselect everything
    sel.removeAllRanges();

    // remove content of current selection from document
    range.deleteContents();

    // get location of current selection
    var container = _container ? _container : range.startContainer; var
    pos = _pos ? _pos : range.startOffset;

    // make a new range for the new selection
    range=doc.createRange();

    if (container.nodeType==3 && insertNode.nodeType==3) {
        // if we insert text in a textnode, do optimized insertion
        container.insertData(pos, insertNode.nodeValue);

        // put cursor after inserted text
        range.setEnd(container, pos+insertNode.length);
        range.setStart(container, pos+insertNode.length);

    } else {
        var afterNode;
        if (container.nodeType==3) {
            // when inserting into a textnode we create 2 new textnodes and
            // put the insertNode in between

            var textNode = container; container = textNode.parentNode; var
            text = textNode.nodeValue;

            // text before the split
            var textBefore = text.substr(0,pos);
            // text after the split
            var textAfter = text.substr(pos);

            var beforeNode = doc.createTextNode(textBefore); afterNode =
            doc.createTextNode(textAfter);

            // insert the 3 new nodes before the old one
            container.insertBefore(afterNode, textNode);
            container.insertBefore(insertNode, afterNode);
            container.insertBefore(beforeNode, insertNode);

            // remove the old node
            container.removeChild(textNode);
        } else {
            // else simply insert the node
            afterNode = container.childNodes[pos];
            container.insertBefore(insertNode, afterNode);
        }
        range.setEnd(afterNode, 0); range.setStart(afterNode, 0);
    }
    sel.addRange(range); return {c:container, p:pos};
}