function checkForm(form) {
  var AtSymbolAt = form.email.value.indexOf('@');
  var LastDotAt = form.email.value.lastIndexOf('.');
  var SpaceAt = form.email.value.indexOf(' ');

 	if(form.email.value.length == 0) {
   	alert("Please enter your Email address.");
   	form.email.focus();
   	return false;
   }

  if(AtSymbolAt < 1 || LastDotAt < AtSymbolAt || form.email.length - LastDotAt <=2) {
   	alert("Please enter a valid Email address.");
   	form.email.focus();
   	return false;
  }
  if(SpaceAt != -1) {
   	alert("No blank spaces are allowed in an email address.(" + SpaceAt+ ")");
   	form.email.focus();
   	return false;
  }
}