给PHP版的高人们一个难题，这个网页的保护功能是如何实现的？？？？

套了个框架...以下为那个页面的源码....
<SCRIPT language=JavaScript>
function doPrint(){
var str="<html>\n<meta http-equiv='content-type' content='text/html; charset=gb2312'>";
var article;
var css;
var strAdBegin="<!--画中画广告开始-->";
var strAdEnd="<!--画中画广告结束-->";
var strTmp;
css="<style>"
+"body{font-family:宋体}"
+"td,.f12{font-size:12px}"
+".f24 {font-size:24px;}"
+".f14 {font-size:14px;}"
+".title14 {font-size:14px;line-height:130%}"
+".l17 {line-height:170%;}"
+".x14 {font-size:14px;line-height:130%}"
+".style5 {color: #FFFFFF}"
+"a:link {text-decoration:none; font-size:12px;color: #000000}"
+"a:visited {text-decoration:none;color:#000000}"
+"a:active {text-decoration:none}"
+"a:hover {color: #FF0000; text-decoration:none}"
+"a.hd:link {text-decoration: none; color: #ffffff;font-size:12px}"
+"a.hd:active {text-decoration:none; color: #ffffff}"
+"a.hd:visited {text-decoration:none;color: #ffffff}"
+"a.hd:hover {text-decoration:none;color: #ff0000} "
+"</style>"; str += css;
str += '<meta http-equiv="content-type" content="text/html; charset=gb2312">';
str += "<body oncontextmenu='return false' onselectstart='return false' ondragstart='return false' bgcolor=#ffffff onkeydown='no_newwin()' oncopy='return false;' oncut='return false;' onmouseover='return true' topmargin=5 leftmargin=5 marginheight=5 marginwidth=5 onLoad='window.print()'>";
str += "<center><table width=700 border=0 cellspacing=0 cellpadding=0><tr><td height=34 width=150><a href=http://www.slqh.com.cn/index.asp><img src=http://www.slqh.com.cn/logo1.jpg width=170 height=40 border=0></a></td><td valign=bottom><font color=#0000ff>"
str += "</font></td><td align=right valign=bottom>【字体：<a class=black href='javascript:doZoom(16)'>大</a>　<a class=black href='javascript:doZoom(14)'>中</a>　<a class=black href='javascript:doZoom(12)'>小</a>】　【<a href='javascript:history.back()'>返回</a>】　【<a href='javascript:window.print()'>打印</a>】</td></tr></table>";
str += "<table width=700 border=0 cellpadding=0 cellspacing=20 bgcolor=#EFEFEF><tr><td><table><tr><td>";
article=document.getElementById('article').innerHTML;
if(article.indexOf(strAdBegin)!=-1){
str +=article.substr(0,article.indexOf(strAdBegin));
strTmp=article.substr(article.indexOf(strAdEnd)+strAdEnd.length, article.length);
}
else{
strTmp=article;
}
str += strTmp;
str += "</td></tr></table>";
str += window.location.href;
str += "</td></tr></table></center>";
str += "</body></html>";
document.write(str);
document.close();
}
function checkname() {
        if(document.pingluntj.nickname.value == '') {
                alert("请输入用户名，谢谢！！");
                return false;
        }
       else if(document.pingluntj.neirong.value == '')
   { 
    alert("内容不能为空");
return false;
}
return true;
}
</script><style type="text/css">
.pt9 {
COLOR: #000000; FONT-FAMILY: "宋体"; FONT-SIZE: 9pt; FONT-WEIGHT: normal; TEXT-DECORATION: none
}
INPUT.Submit {height=23;border:1 solid #dd0000;BACKGROUND-COLOR:#ffffff;FONT-SIZE: 11pt ;font-color:#cccc00; PADDING-TOP: 1px}
a.hd:link {text-decoration: none; color: #ffffff}
a.hd:active{text-decoration:none; color: #ffffff}
a.hd:visited{text-decoration:none;color: #ffffff}
a.hd:hover{text-decoration:none;color: #ff0000} 
a:link {  text-decoration: none; color: #000000}
a:hover {  color: #FF0000; text-decoration: none}
a:visited{text-decoration:none} 
a:active{text-decoration:none}
blockquote {  font-family: "宋体"; font-size: 14px; line-height: 18pt; color: #000000; letter-spacing: 2px; text-align: justify}
body {  font-family: "宋体"; font-size: 12px; line-height: 17pt; color: #000000; letter-spacing: 1px}
td {  font-family: "宋体"; font-size: 12px; line-height: 17pt; color: #000000; letter-spacing: 1px}
.eng {
FONT-SIZE: 11px;
FONT-FAMILY: arial, helvetica;
color: #FFFFFF;
}
.black { FONT-SIZE: 12px; COLOR: #000000; LINE-HEIGHT: 19px; TEXT-DECORATION: none
}
.style2 {color: #333333}
.style3 {color: #000000}
.style5 {color: #FFFFFF}
</style>