function validation(form) {
          
if(form.first_name.value == '') {

alert('Please enter your first name');
form.first_name.focus();
return false;
}


if(form.last_name.value == '') {

alert('Please enter your last name');
form.last_name.focus();
return false;
}

if(form.email.value == '') {

alert('Please enter your email address');
form.email.focus();
return false;
}

var re = /^([\w-\.\+']+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$/;
var m = re.exec(form.email.value);
if (m == null) {
    alert("Please enter a valid email address.");
	form.email.focus();	
	return false; 
}

if(form.phone.value == '') {

alert('Please enter your phone number');
form.phone.focus();
return false;
}

return true;
}