中级深入篇
上篇中是采用JavaScript技术达到保护在线网页的目的.正所谓"强中自有强中手",有些人使用Webzip,TelePro,Offline等离线浏览器下载你的主页,就可绕过JavaScript保护在线网页的防线,将网页下载后再慢慢剖析.有矛必有盾,你亦可用JavaScript建立的动态转向文件是大多数离线浏览器无法下载你的网页,方法如下.你可将上例中的被保护页面更名为index1.html,而将文件index.html改为以下代码:
<script>
window.location.replace(\'index1.html\') //本句产生网页跳转功能
</script>
对Internet Explorer5新增的离线浏览功能(脱机工作),以上方法有时失灵,可通过对网页设置cookie的高级技术达到保护的目的.一旦cookie超期,即使网页已被下载到本机也无法浏览,呵呵,厉害吧:)
应加入文件中的cookie代码段如下:
<script language="JavaScript">
function getCookieVal (offset)
{
var endstr = document.cookie.indexOf (";", offset);
if (endstr == -1)
endstr = document.cookie.length;
return unescape(document.cookie.substring(offset, endstr));
}
function GetCookie (name)
{
var arg = name + "=";
var alen = arg.length;
var clen = document.cookie.length;
var i = 0;
while (i < clen)
{
var j = i + alen;
if (document.cookie.substring(i, j) == arg)
return getCookieVal (j);
i = document.cookie.indexOf(" ", i) + 1;
if (i == 0)
break;
}
return null;
}
function SetCookie (name, value)
{
var argv = SetCookie.arguments;
var argc = SetCookie.arguments.length;
var expires = (2 < argc) ? argv[2] : true;
var path = (3 < argc) ? argv[3] : true;
var domain = (4 < argc) ? argv[4] : true;
var secure =
(5 < argc) ? argv[5] : true; //安全模式生效
document.cookie = name + "=" + escape (value) +
((expires == null) ? "" : ("; expires=" + expires.toGMTString())) +
((path == null) ? "" : ("; path=" + path)) +
((domain == null) ? "" : ("; domain=" + domain)) +
((secure == true) ? "; secure" : "");
}
function ResetCounts(name)
{
visits = 0;
SetCookie(expdate , "/", true, true);
location.reload();
}
</script>
<script language="JavaScript">
var expdate = new Date();
var visits;
expdate.setTime(expdate.getTime() + (24*60*60 * 1000)); //COOKIES超期时间设置,此处为1天
if(!(visits = GetCookie("visits")))
visits = 0;
visits++;
SetCookie(expdate, "/", true, true);
</script>
如果你已经做到这一步了,那么你的网页所受到的保护就不再是常规意义上的出于道德观念或版权意识,而是真正的技术上的保护手段.