Onblur not working ?

Hi friends

Well i hope my code is correct 


protected void Page_Load(object sender, EventArgs e)
    {
        TextBox1.Attributes.Add("onblur","ValidatorsValidate("+RequiredFieldValidator1.ClientID+"+)");
       
    }



My basic need is when i don't enter anything in text-box and press tab key or enter key likely the focus shouldn't shift from my text-box until unless i enter something ??


I hope the above code is for that purpose only ?? 


Ty