// JavaScript Document

function trim(s) {
	while(s.length>0 && s.substring(s.length-1,s.length)==' ')
		s=s.substring(0, s.length-1);

	if(s.length==1 && s==' ')
		s='';

	return s;
}

function empty(s) {
	s=trim(s);
	return(s.length==0);
}

function errorFocus(s, focusField) {
			 
 if(!empty(s)) alert(s);
 focusField.focus();
 
 return false;
}

function validateComment() {
	
	with(document.commentForm) {
		
		if(empty(nickname.value)) return errorFocus("Please enter a Name.", nickname);
		if(empty(comment.value)) return errorFocus("Please enter a Comment.", comment);
	
	}
}