[MarkFL]

Because of an issue reported to me by one of my fellow administrators, who uses a different OS (I use Windows 7 and he uses Xubuntu and we both use Firefox), I have moved the focus method to the end of the moveCaret function, and this alleviates the need to make two calls to the moveCaret function (which I used previously so that Chrome did not lose the cursor).

So, the updated functions are:

function copyMathToPost()
{
    var content = document.getElementById('MathInput').value, el = document.getElementsByClassName('cke_source')[0];
    if (el)
    {
        var pos = getCaretPosition(el);
        el.value = el.value.substr(0, pos) + content + el.value.substr(pos);
        setCaretPosition(el,pos + content.length);
        el.focus();
    }
    else
    {
        var iFrame = document.getElementsByTagName('iframe')[0];
        insertHtmlAtCursor(iFrame,content);
        moveCaret(iFrame, 0);
    }
}

function insertHtmlAtCursor(iFrame,html)
{
    var sel, range, node;
    html = html.replace(/\r\n?|\n/g, '<br>');
    if (iFrame.contentWindow.getSelection && iFrame.contentWindow.getSelection().getRangeAt)
    {
        sel = iFrame.contentWindow.getSelection();
        try{range = sel.getRangeAt(0);}
        catch (e){alert("This function is not supported by your browser. Please switch editor to Source Mode.");}
        node = range.createContextualFragment(html);
        range.insertNode(node);
        range = range.cloneRange();
        range.collapse();
        sel.removeAllRanges();
        sel.addRange(range);
    }
    else if (iFrame.contentWindow.selection && iFrame.contentWindow.selection.createRange)
    {
        iFrame.contentWindow.selection.createRange().pasteHTML(html);
    }
    else
    {
        alert("This function is not supported by your browser. Please switch editor to Source Mode.");
    }
}

function moveCaret(win, charCount)
{
    var sel, range;
    if (win.contentWindow.getSelection)
    {
        sel = win.contentWindow.getSelection();
        if (sel.rangeCount > 0)
        {
            var textNode = sel.focusNode;
            var newOffset = sel.focusOffset + charCount;
            sel.collapse(textNode, newOffset);
        }
    }
    else if (sel = win.contentDocument.selection)
    {
        if (sel.type != "Control")
        {
            range = sel.createRange();
            range.move("character", charCount);
            range.select();
        }
    }
    win.focus();
}