function ValidateForm(form)
{

   if (form.name.value == "") 
   { 
      alert('You have not entered a name') 
      form.name.focus(); 
      return false;
  }
  
    if (form.mainphone.value == "") 
   { 
      alert('You have not entered a phone number') 
      form.mainphone.focus(); 
      return false; 
   } 
       if (form.email.value == "") 
   { 
      alert('You have not entered an email address') 
      form.email.focus(); 
      return false; 
   } 
 
   var x = form.email.value;
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (filter.test(x)) 
	{
		
	}
	else 
	{
		alert('Sorry, your email is not in the correct format')
	form.email.focus(); 
    return false;
    }

    
return true;
 
 
}