function validate_Email(field,alerttxt)
{
with (field)
  {
  apos=value.indexOf("@");
  dotpos=value.lastIndexOf(".");
  if (apos<1||dotpos-apos<2)
    {alert(alerttxt);return false;}
  else {return true;}
  }
}

function validate_form(thisform)
{
with (thisform)
  {
  if (validate_Email(Email,"Please provide a valid e-mail address.")==false)
    {Email.focus();return false;}	
  }
}