function validavacio (Ctrl) {
			if (Ctrl.value == "" || Ctrl.value.length == 0){
				//alert('V');
				return true;
			} else{
				//alert('F');
				return false;}
}

function validemail(Ctrl) {
			if (Ctrl.value == "" || Ctrl.value.indexOf ('@', 0) == -1 || Ctrl.value.indexOf ('.', 0) == -1)
				return true;
			else
				return false;
		}

function button_onclick_login()
{
if (validemail(document.login.username)){ 
   alert("Por favor ingrese email de Usuario"); 
	 document.login.username.focus();
   return false; 
}
if (validavacio(document.login.password)){ 
    alert("Por favor ingrese password"); 
		document.login.password.focus();
    return false; 
}
document.login.submit()
}