function ubb(field, tag)
{
    obj_txtarea = document.getElementById(field);

    obj_field = document.getElementById(field);

    function mozilla(obj_txtarea, open, close)
    {
        var selLength = obj_txtarea.textLength;
        var selStart = obj_txtarea.selectionStart;
        var selEnd = obj_txtarea.selectionEnd;
        if (selEnd == 1 || selEnd == 2)
        {
            selEnd = selLength;
        }
        var s1 = (obj_txtarea.value).substring(0,selStart);
        var s2 = (obj_txtarea.value).substring(selStart, selEnd)
        var s3 = (obj_txtarea.value).substring(selEnd, selLength);
        obj_txtarea.value = s1 + open + s2 + close + s3;
        return;
    }

    if (document.selection)
    {
        if (document.selection.createRange().text.length > 0)
        {
            if (tag == 'url')
            {
                var link = prompt('Wat is de website?', 'http://');

                if (link.length > 7)
                {
                    selected = document.selection.createRange().text;
                    document.selection.createRange().text = '[' + tag + '="' + link  + '"]' + selected + '[/' + tag +  ']';
                    selected = '';
                    return;
                }
                else
                {
                    return false;
                }
            }
            else if (tag == 'url2')
            {
                var link = prompt('Wat is de website?', 'http://');

                if (link.length > 7)
                {
                    selected = document.selection.createRange().text;
                    document.selection.createRange().text = '[url="' + link  + '" target="_blank"]' + selected + '[/url]';
                    selected = '';
                    return;
                }
                else
                {
                    return false;
                }
            }
            else if (tag == 'h')
            {
                selected = document.selection.createRange().text;
                document.selection.createRange().text = '[' + tag + ']' + selected + '[/' + tag +  ']\n';
                selected = '';
                return;
            }
            else
            {
                selected = document.selection.createRange().text;
                document.selection.createRange().text = '[' + tag + ']' + selected + '[/' + tag +  ']';
                selected = '';
                return;
            }
        }
        else
        {
            alert('U dient de tekst te selecteren die je wilt opmaken.');
        }
    }
    else if (obj_txtarea.selectionEnd && (obj_txtarea.selectionEnd - obj_txtarea.selectionStart > 0))
    {
        if (tag == 'url')
        {
            var link = prompt('Wat is de website?', 'http://');
            if (link.length > 7)
            {
                mozilla(obj_txtarea, '[' + tag + '="' + link + '"]', '[/' + tag + ']');
            }
            else
            {
                return false;
            }
        }
        else if (tag == 'url2')
        {
            var link = prompt('Wat is de website?', 'http://');
            if (link.length > 7)
            {
                mozilla(obj_txtarea, '[url="' + link + '" target="_blank"]', '[/url]');
            }
            else
            {
                return false;
            }
        }
        else if (tag == 'h')
        {
            mozilla(obj_txtarea, '[' + tag + ']', '[/' + tag + ']\n');
        }
        else
        {
            mozilla(obj_txtarea, '[' + tag + ']', '[/' + tag + ']');
        }
        return;
    }
    else
    {
        alert('U dient de tekst te selecteren die je wilt opmaken.');
    }

    obj_field.focus();
    return;
}