function validateFormData(form) 
{
//  alert('Checking your form data...');
  var errorMsg = '';
  
  // Test that all the required fields are filled out ok	 
 
 // begin email string
  if (form.email.value == "" )
  {
    errorMsg += 'Your email address is required\n';
	form.email.focus();
  }
  else
  {
	x = form.email.value.indexOf('@');
	y = form.email.value.indexOf('.');

    if (x < 1 || x == (form.email.value.length-1) || y < 1 ) 
	{
	  errorMsg += 'You must give a valid email address.\n';
	  form.email.focus();
	  form.email.select();
	}
	  
    s = form.email.value.indexOf(' ');
    if (s != -1)
	{
	  errorMsg += 'Please check your email address. It should not contain or have leading/trailing spaces\n';
	  form.email.focus();
	  form.email.select();
	}
  }	
 // end of email string]
 
 // required elements

    if (form.first_name.value == "" || form.first_name.value == "Required field")
    errorMsg += 'Your first name is required\n';	

    if (form.surname.value == "" || form.surname.value == "Required field")
    errorMsg += 'Your surname is required\n';		

    if (form.phone.value == "" || form.phone.value == "Required field")
    errorMsg += 'Your telephone number is required\n';	
 
 
  // closing string 
  if (errorMsg) 
	alert('Required form fields:\n'+errorMsg);
  document.returnValue = (errorMsg == '');
}