哪位帮我解释一下,,这段代码,,谢谢了

<%@page contentType="text/html; charset=gb2312" language="java" import="java.sql.*"  errorPage="err.jsp"%>
<html>
<head>
<META NAME="keywords" CONTENT="*****java forum jsp forum">
<META NAME="description" CONTENT="*****java forum jsp forum">
<link rel='stylesheet' type='text/css' href='inc/FORUM.CSS'>
<script language="JavaScript"> 
function Popup(url, window_name, window_width, window_height) 
{ settings= 
"toolbar=no,location=no,directories=no,"+ 
"status=no,menubar=no,scrollbars=yes,"+ 
"resizable=yes,width="+window_width+",height="+window_height; NewWindow=window.open(url,window_name,settings); }function icon(theicon) { 
document.input.message.value += " "+theicon; 
document.input.message.focus();