function checkcontactform() {
	var errormsgtemp = '';
	var errormsg	 = '';
	// Check user has included name
	if (document.contactform.name.value == "") 
	{
		document.contactform.name.style.border = '1px solid #FF0000';
		var errormsg = "Your name is blank.\n";
	} else { document.contactform.name.style.border = '0px;'; }
	// Check user telephone number is completely numeric
     rePhoneNumber =/(^\d+$)|(^\d+\.\d+$)/
	 phonenumber= document.contactform.telephone_number.value
     if (phonenumber == '') {
		var errormsgtemp = errormsg;
		var errormsg = errormsgtemp+"Telephone number is blank.\n";
		document.contactform.telephone_number.style.border = '1px solid #FF0000';
     } else { document.contactform.telephone_number.style.border = '0px;'; }

	// Check email address fits valid format
	var x = document.contactform.email_address.value;
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (filter.test(x)) 
	{
			document.contactform.email_address.style.border = '0px;';
	} else {
			document.contactform.email_address.style.border = '1px solid #FF0000';
			var errormsgtemp = errormsg;			
			var errormsg = errormsg+"Email address is not valid. Please check.\n";
	}
	// Check the message is filled in 
	if (document.contactform.message.value == "") 
	{
		document.contactform.message.style.border = '1px solid #FF0000';
		var errormsgtemp = errormsg;
		var errormsg = errormsg+"Your message is blank.\n";
	} else { document.contactform.message.style.border = '0px;'; }
	
	// Now check errormsg is blank return true, otherwise alert and return false
	if (errormsg == '') { return true; } else { alert(errormsg); return false; }
}