String.prototype.trim = function() { return this.replace(/^\s+|\s+$/g, ''); }


function checkEmail(email) {
	if (/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(email)){
		return true;
	}else{		
		return false;
	}
}

function checkForm() {
	var enroll = document.form1.enroll.checked;
	var update = document.form1.update.checked;
	var newsletter = document.form1.newsletter.checked;
	var visit = document.form1.visit.checked;
	
	if ( !( enroll || update || newsletter || visit ) ) {
		alert( 'Please check at least one checkbox at the top of the page.' ); 
		return false;
	}
	
	if ( document.form1.name.value.trim() == '' ) {
		alert( 'Please enter your name.' );
		document.form1.name.focus();
		return false;
	}
	
	if ( document.form1.title.value.trim() == '' ) {
		alert( 'Please enter your title.' );
		document.form1.title.focus();
		return false;
	}
	
	if ( document.form1.company.value.trim() == '' ) {
		alert( 'Please enter your company/association name.' );
		document.form1.company.focus();
		return false;
	}
	
	if ( document.form1.address.value.trim() == '' ) {
		alert( 'Please enter your address.' );
		document.form1.address.focus();
		return false;
	}
	
	if ( document.form1.city.value.trim() == '' ) {
		alert( 'Please enter your city.' );
		document.form1.city.focus();
		return false;
	}
	
	if ( document.form1.country.value.trim() == '' ) {
		alert( 'Please enter your country.' );
		document.form1.country.focus();
		return false;
	}
	
	if ( document.form1.zip.value.trim() == '' ) {
		alert( 'Please enter your zip code.' );
		document.form1.zip.focus();
		return false;
	}
	
	if ( !checkEmail( document.form1.email.value ) ) {
		alert( 'Please enter a valid email address.' );
		document.form1.email.focus();
		return false;
	}
	
	if ( document.form1.employees.value.trim() == '' ) {
		alert( 'Please enter the number of employees in your company.' );
		document.form1.employees.focus();
		return false;
	}
	
	if ( document.form1.cards2008.value.trim() == '' ) {
		alert( 'Please enter the number of cards you need for 2008.' );
		document.form1.cards2008.focus();
		return false;
	}
	
	return true;
}