replace innerHTML in contenteditable div

Question

i need to implement highlight for numbers( in future im add more complex rules ) in the contenteditable div. The problem is When im insert new content with javascript replace, DOM changes and contenteditable div lost focus. What i need is keep focus on div with caret on the current position, so users can just type without any issues and my function simple highlighting numbers. Googling around i decide that Rangy library is the best solution. I have following code:

function formatText() {
         
              var savedSel = rangy.saveSelection();
              el = document.getElementById('pad');
              el.innerHTML = el.innerHTML.replace(/(<([^>]+)>)/ig,"");
              el.innerHTML = el.innerHTML.replace(/([0-9])/ig,"<font color='red'>$1</font>");
              rangy.restoreSelection(savedSel);
          }

<div contenteditable="true" id="pad" onkeyup="formatText();"></div>

The problem is after function end work focus is coming back to the div, but caret always point at the div begin and i can type anywhere, execept div begin. Also console.log types following Rangy warning: Module SaveRestore: Marker element has been removed. Cannot restore selection. Please help me to implement this functional. Im open for another solutiona, not only rangy library. Thanks!

http://jsfiddle.net/2rTA5/ This is jsfiddle, but it dont work properly(nothing happens when i typed numbers into my div), dunno maybe it me (first time post code via jsfiddle) or resource doesnt support contenteditable. UPD* Im read similar problems on stackoverflow, but solutions doesnt suit to my case :(

Answer 1

The problem is that Rangy's save/restore selection module works by inserting invisible marker elements into the DOM where the selection boundaries are and then your code strips out all HTML tags, including Rangy's marker elements (as the error message suggests). You have two options:

1. Move to a DOM traversal solution for colouring the numbers rather than innerHTML. This will be more reliable but more involved.
2. Implement an alternative character index-based selection save and restore. This would be generally fragile but will do what you want in this case.

UPDATE

I've knocked up a character index-based selection save/restore for Rangy (option 2 above). It's a little rough, but it does the job for this case. It works by traversing text nodes. I may add this into Rangy in some form. (UPDATE 5 June 2012: I've now implemented this, in a more reliable way, for Rangy.)

jsFiddle: http://jsfiddle.net/2rTA5/2/

Code:

function saveSelection(containerEl) {
    var charIndex = 0, start = 0, end = 0, foundStart = false, stop = {};
    var sel = rangy.getSelection(), range;

    function traverseTextNodes(node, range) {
        if (node.nodeType == 3) {
            if (!foundStart && node == range.startContainer) {
                start = charIndex + range.startOffset;
                foundStart = true;
            }
            if (foundStart && node == range.endContainer) {
                end = charIndex + range.endOffset;
                throw stop;
            }
            charIndex += node.length;
        } else {
            for (var i = 0, len = node.childNodes.length; i < len; ++i) {
                traverseTextNodes(node.childNodes[i], range);
            }
        }
    }

    if (sel.rangeCount) {
        try {
            traverseTextNodes(containerEl, sel.getRangeAt(0));
        } catch (ex) {
            if (ex != stop) {
                throw ex;
            }
        }
    }

    return {
        start: start,
        end: end
    };
}

function restoreSelection(containerEl, savedSel) {
    var charIndex = 0, range = rangy.createRange(), foundStart = false, stop = {};
    range.collapseToPoint(containerEl, 0);

    function traverseTextNodes(node) {
        if (node.nodeType == 3) {
            var nextCharIndex = charIndex + node.length;
            if (!foundStart && savedSel.start >= charIndex && savedSel.start <= nextCharIndex) {
                range.setStart(node, savedSel.start - charIndex);
                foundStart = true;
            }
            if (foundStart && savedSel.end >= charIndex && savedSel.end <= nextCharIndex) {
                range.setEnd(node, savedSel.end - charIndex);
                throw stop;
            }
            charIndex = nextCharIndex;
        } else {
            for (var i = 0, len = node.childNodes.length; i < len; ++i) {
                traverseTextNodes(node.childNodes[i]);
            }
        }
    }

    try {
        traverseTextNodes(containerEl);
    } catch (ex) {
        if (ex == stop) {
            rangy.getSelection().setSingleRange(range);
        } else {
            throw ex;
        }
    }
}

function formatText() {
    var el = document.getElementById('pad');
    var savedSel = saveSelection(el);
    el.innerHTML = el.innerHTML.replace(/(<([^>]+)>)/ig,"");
    el.innerHTML = el.innerHTML.replace(/([0-9])/ig,"<font color='red'>$1</font>");

    // Restore the original selection
    restoreSelection(el, savedSel);
}