function checkForm (form){
  for (var i = 0; i < form.elements.length; i++){
    if ((form.elements[i].className == "required_field") && (form.elements[i].value =="")){
	  var requiredField = form.elements[i].name
		  requiredField = requiredField.replace("_"," ");
		  requiredField = requiredField.toUpperCase();
	  alert("Please enter your " + requiredField +".");
	  form.elements[i].style.backgroundColor="lightyellow";
	  form.elements[i].focus();
	  return false;
	} else if ((form.elements[i].className == "required_field") && (form.elements[i].name == "email") && (form.elements[i].value.indexOf("@") == -1)){
		alert("Please enter a valid email address!");
		form.elements[i].style.backgroundColor="lightyellow";
		form.elements[i].focus();
		form.elements[i].select();
	  	return false;
		} else if ((form.elements[i].className == "required_field") && (form.elements[i].name == "email") && (form.elements[i].value.indexOf(".") == -1)){
			alert("Please enter a valid email address!");
			form.elements[i].style.backgroundColor="lightyellow";
			form.elements[i].focus();
			form.elements[i].select();
	  		return false;
			} else if ((form.elements[i].name == "email") && (form.elements[i].value != "")){
	 			if ((form.elements[i].value.indexOf("@") == -1) || (form.elements[i].value.indexOf(".") == -1)){
					alert("Please enter a valid email address!");
					form.elements[i].style.backgroundColor="lightyellow";
					form.elements[i].focus();
					form.elements[i].select();
	  				return false;
  	 			}
			  }
  } 
  return true;
}