function formatText(el,tagstart,tagend) {

    if (el.setSelectionRange) {
        el.value = el.value.substring(0,el.selectionStart) + tagstart + el.value.substring(el.selectionStart,el.selectionEnd) + tagend + el.value.substring(el.selectionEnd,el.value.length);
    } else {
        var selectedText = document.selection.createRange().text;
       
        if (selectedText != '') {
            var newText = tagstart + selectedText + tagend;
            document.selection.createRange().text = newText;
        }
    }
}