function checkValid( theForm ) {
	var errMsg = '';
	if( !theForm.toTarquin.checked && !theForm.toChris.checked && !theForm.toOther.value ) { window.alert( 'You must choose at least one recipient.'); return false; }
	if( !theForm.senderName.value ) { errMsg += '\n\n  You should supply a name, or your message may be deleted without being read.'; }
	if( !theForm.senderEmail.value || theForm.senderEmail.value.replace( /[\w\-]+(\.[\w\-]+)*@[\w\-]+(\.[\w\-]+)+/i, "" ) ) {
		errMsg += '\n\n  You do not seem to have supplied a valid email address (this will be confirmed by the server). If you do not supply a valid email address, your message will not be sent.'; }
	if( !theForm.subject.value ) {
		errMsg += '\n\n  You have not supplied a subject. If you do not supply a subject, a default one will be used.'; }
	if( !theForm.message.value ) { window.alert( 'You have not supplied a message. There is nothing to send.'); return false; }
	if( errMsg ) { return window.confirm('The following problems were encountered:'+errMsg+'\n\nDo you want to try to continue anyway?'); }
	return true;
}