function isEmailAddress(string) {
    return /^[^@]+@[^.]+(\.[^.]+)+$/.test(string);
}

function validate(form) {
    var noerror = true;
    var invalidemail = false;
    var ischecked = false;
    var controls = form.elements,
        emailAddress = controls['email'].value;
        first = controls['first_name'].value;
        last = controls['last_name'].value;
        country = controls['country'].value;
        interest = controls['00N70000002iTRZ'].value;

  
   	  
   	  if(first== ''){
   		alert('Please enter a valid First Name');
   	   	return false;
   		  
   	  }
   	  if(last== ''){
     		alert('Please enter a valid Last Name');
     	   	return false;
     		  
      }
   	  if(!isEmailAddress(emailAddress))
   	  {
   	   	alert('Please enter a valid Email Address');
   	   	return false;
   	  }
   	  if(country==''){
     		alert('Please enter a valid Country');
     	   	return false;
     		  
       }
  
}