function validate_form() {
  var currentForm = document.productForm;

  if (currentForm.Name.value == "")
  {	
  	alert("Please enter your Name");
  	currentForm.Name.focus();
  	return false;
  }

  if (currentForm.Company.value == "")
  {	
  	alert("Please enter your Company");
  	currentForm.Company.focus();
  	return false;
  }

  if (currentForm.Email.value == "")
  {	
    alert("Please provide your email address so that our staff may contact you.");
  	currentForm.Email.focus();
  	return false;
  }

  if (!validEmail(currentForm.Email)) {
     alert("Please provide a valid email address so that our staff may contact you.");
     currentForm.Email.focus();
     return false;
  } 

  if ( (currentForm.Tel.value == null) ||
       (currentForm.Tel.value == "") )
  {	
  	alert("Please enter your Telephone Number so that our staff may contact you.");
  	currentForm.Tel.focus();
  	return false;
  }

  if (currentForm.ProductList.selectedIndex == 0 || 
      currentForm.ProductList.selectedIndex == 1)
  {	
      alert("Please select the product that you're interested.");
      currentForm.ProductList.focus();
      return false;
  }

  if (currentForm.Enquiry.value == "")
  {	
  	alert("Please provide more information under Enquiry details so that our staff can assist you accordingly. Thanks.");
  	currentForm.Enquiry.focus();
  	return false;
  }
}

function validEmail(email){
	if (email.value.length > 0) {
		var filter = /^[a-zA-Z0-9]([a-zA-Z0-9_\.\-\+])*\@([a-zA-Z0-9]([a-zA-Z0-9\-])*\.)+([a-zA-Z0-9])+$/;
		
		if (!filter.test(email.value)) {			
		        return false;
		}
	} 
	return true;
}