/**
	 * Checks that necessary details are filled in correctly.
	 */
	function validate_form(form, txt) {
		if(!form.Name.value || form.Name.value == "") {
			form.Name.focus();
			alert("You must enter your name.");
			return false;
		}
		
		if(!form.email_address.value || form.email_address.value == "") {
			form.email_address.focus();
			alert("You must enter your email address.");
			return false;
		} else if(form.email_address.value.search(/^.+@.+$/i) == -1) {
            form.email_address.focus();
            form.email_address.select();
            alert("You must enter a full email address.");
            return false;
        }
			
		if(!form.email_2.value || form.email_2.value == "") {
			form.email_2.focus();
			alert("You must confirm your email address.");
			return false;
		}
		
		if(form.email_address.value.toLowerCase() != form.email_2.value.toLowerCase()) {
			form.email_2.focus();
			form.email_2.select();
			alert("Please check your email address is correct in both boxes.");
			return false;
		}
		
		if(txt && (!form.Enquiry.value || form.Enquiry.value == "")) {
			form.Enquiry.focus();
			alert("You must enter " + txt + ".");
			return false;
		}
		
		return true;
	}