function insertTab(event, obj)  
{  
    var tabKeyCode = 9;  
    if (event.which) // mozilla  
        var keycode = event.which;  
    else // ie  
        var keycode = event.keyCode;  
  
    if (keycode == tabKeyCode)  
    {  
        if (event.type == "keydown")  
        {  
            var oldscroll = obj.scrollTop;  
  
            if (obj.setSelectionRange)  
            {  
                // mozilla  
                var s = obj.selectionStart;  
                var e = obj.selectionEnd;  
                obj.value = obj.value.substring(0, s) + "\t" + obj.value.substr(e);  
                obj.setSelectionRange(s + 1, s + 1);  
                obj.focus();  
            }  
            else if (obj.createTextRange)  
            {  
                // ie  
                document.selection.createRange().text = "\t"  
                obj.onblur = function() { this.focus(); this.onblur = null; };  
            }  
  
            obj.scrollTop = oldscroll;  
        }  
  
        if (event.returnValue) // ie ?  
            event.returnValue = false;  
        if (event.preventDefault) // dom  
            event.preventDefault();  
        return false; // should work in all browsers  
    }  
    return true;  
}