javascript实现动态CSS换肤技术的脚本_javascript技巧

<SCRIPT LANGUAGE=javascript>    
<!--    
function SetCookie(name,value){    
    var argv=SetCookie.arguments;    
    var argc=SetCookie.arguments.length;    
    var expires=(2<argc)?argv[2]:null;    
    var path=(3<argc)?argv[3]:null;    
    var domain=(4<argc)?argv[4]:null;    
    var secure=(5<argc)?argv[5]:false;    
    document.cookie=name+"="+escape(value)+((expires==null)?"":("; expires="+expires.toGMTString()))+((path==null)?"":("; path="+path))+((domain==null)?"":("; domain="+domain))+((secure==true)?"; secure":"");    
}    

function GetCookie(Name) {    
    var search = Name + "=";    
    var returnvalue = "";    
    if (document.cookie.length > 0) {    
          offset = document.cookie.indexOf(search);    
          if (offset != -1) {          
                offset += search.length;    
                end = document.cookie.indexOf(";", offset);                            
                if (end == -1)    
                      end = document.cookie.length;    
                returnvalue=unescape(document.cookie.substring(offset,end));    
          }    
    }    
    return returnvalue;    
}    

var thisskin;    
thisskin=GetCookie("nowskin");    
if(thisskin!="")    
    skin.href=thisskin;    
else   
    skin.href="css.css";    

function changecss(url){    
    if(url!=""){    
          skin.href=url;    
          var expdate=new Date();    
          expdate.setTime(expdate.getTime()+(24*60*60*1000*30));    
          //expdate=null;    
                                  //以下设置COOKIES时间为1年,自己随便设置该时间..    
          SetCookie("nowskin",url,expdate,"/",null,false);    
    }    
}    
//-->    
</SCRIPT> 
<P>请选择下面的下拉菜单测试换肤效果</P>   

<a href=# onclick="changecss('css.css')">css.css</a>   
<a href=# onclick="changecss('css1.css')">css1.css</a>   
<a href=# onclick="changecss('css2.css')">css2.css</a>   
<a href=# onclick="changecss('css3.css')">css3.css</a>   
<br>   

<select onchange="changecss(this.value)">   
<option>选择样式单文件</option>   
<script language="javascript">   
var csss=new Array();    
csss[0]="css.css";    
csss[1]="css1.css";    
csss[2]="css2.css";    
csss[3]="css3.css";    
var i;    
for(i=0;i<4;i++)    
    if(thisskin==csss[i])    
          document.write("<option value=\""+csss[i]+"\" selected>"+csss[i]+"样式单文件</option>");    
    else    
          document.write("<option value=\""+csss[i]+"\">"+csss[i]+"样式单文件</option>");    
</script>   
</select>