public static String htmlq(String html) {
	if(html == null)
	    return("(null)");
	StringBuilder buf = new StringBuilder();
	for(int i = 0; i < html.length(); i++) {
	    char c = html.charAt(i);
	    if(c == '&')
		buf.append("&amp;");
	    else if(c == '<')
		buf.append("&lt;");
	    else if(c == '>')
		buf.append("&gt;");
	    else
		buf.append(c);
	}
	return(buf.toString());
    }