[求助]这段是什么意思？java script

<SCRIPT type="text/javascript">
        var browserOS=navigator.userAgent;
//only when on linux, check and ask to download
if(browserOS.lastIndexOf('Linux') != -1){
         var   javaPlugin= 0;
         for (i=0; i < navigator.plugins.length; i++) {
                if(navigator.plugins.name>='Java(TM) Plug-in 1.4.2_03-b02'){
                        javaPlugin++;
                }
         }
         if(javaPlugin<1){
                 alert("The required Java plugin is not installed on your machine, please follow the instruction to install it.");
document.location="jvmDownload.html";
}
}
</SCRIPT>

还有这些，他们上下联系的


<script type="text/javascript">
<!--
  // Put the cursor into the first field
  document.LOGIN.uid.focus();
// -->
</script>

检测有没有装JRE

我记得楼主很Niu的啊.........

rangnisiwangle