function checkForm() {
	// Checking the validity of email addresses with the following regular expressions
  	var email_regexp = /^.+\@(\[?)[a-zA-Z0-9\-\.]+\.([a-zA-Z]{2,3}|[0-9]{1,3})(\]?)$/; // valid
	var phone_regexp = /^([0-9\s-.\(\)]+)$/; // valid
	var zipcode_regexp = /^([0-9\s-]+)$/; // valid
	for (var i = 0; i < document.rsvp_form.member.length; i++)
	{
		if (document.rsvp_form.member[i].checked)
		{
			member = document.rsvp_form.member[i].value;
			break;
   		}
	}
	
	if (document.rsvp_form.fname.value == "") {
    	alert("Please provide a first name.");
        return false;
   	}
	if (document.rsvp_form.lname.value == "") {
    	alert("Please provide a last name.");
        return false;
   	}
	if (document.rsvp_form.attendees.value < 1) {
    	alert("Please provide a valid number of attendees.");
        return false;
   	}
	if (document.rsvp_form.attendees.value > 10) {
    	alert("Please note: only ten people in your party are eligible for Members early seating. If you have questions, or for special circumstances, please contact the Membership Department at (213) 744-7504.");
        return false;
   	}
	if (document.rsvp_form.email.value == "" || !email_regexp.test(document.rsvp_form.email.value)) {
    	alert("Please provide a proper email address.");
        return false;
   	}
	if (document.rsvp_form.zipcode.value != "" && !zipcode_regexp.test(document.rsvp_form.zipcode.value)) {
    	alert("Please provide a proper zipcode.");
        return false;
   	}
	if (document.rsvp_form.attendees.value < 1) {
    	alert("Please provide a valid number of attendees.");
        return false;
   	}
	return true;
}