var alertcounter;
alertcounter = 0;

function form_check()
{
	if(alertcounter == 0)
	  {
		if (document.Logon.txtUserName.value == '')
		{
			alert("USERNAME is a required field.");
			return false;
		}

		if (document.Logon.txtPassword.value == '')
		{
			alert("PASSWORD is a required field.");
			return false;
		}
	 }
	 else
		{alertcounter = 0;return false;}	

	return true;
}

function email_check()
{
	if (document.Logon.txtEmailAddress.value == '')
	{
		alert("Email Address is a required field.");
		alertcounter = alertcounter + 1;
		return false;
	}
    alertcounter = alertcounter + 1;
	return true;
}

function checkenter()
{
	if (window.event && window.event.keyCode == 13)
	{
	document.Logon.btnSend.click();
	return false;
	}
}