js之判断浏览器类型及版本号

function browserinfo(){
         var Browser_Name = navigator.appName;
         var Browser_Version = parseFloat(navigator.appVersion);
         var Browser_Agent = navigator.userAgent;
        
         var Actual_Version,Actual_Name;
        
         var is_IE = (Browser_Name == " Microsoft Internet Explorer " );
         var is_NN = (Browser_Name == " Netscape " );
        
         if (is_NN){
             // upper 5.0 need to be process,lower 5.0 return directly
             if (Browser_Version >= 5.0 ){
                 var Split_Sign = Browser_Agent.lastIndexOf( " / " );
                 var Version = Browser_Agent.indexOf( " " ,Split_Sign);
                 var Bname = Browser_Agent.lastIndexOf( " " ,Split_Sign);

                 Actual_Version = Browser_Agent.substring(Split_Sign + 1 ,Version);
                 Actual_Name = Browser_Agent.substring(Bname + 1 ,Split_Sign);
             }
             else {
                 Actual_Version = Browser_Version;
                 Actual_Name = Browser_Name;
             }
         }
         else if (is_IE){
             var Version_Start = Browser_Agent.indexOf( " MSIE " );
             var Version_End = Browser_Agent.indexOf( " ; " ,Version_Start);
             Actual_Version = Browser_Agent.substring(Version_Start + 5 ,Version_End)
             Actual_Name = Browser_Name;
            
             if (Browser_Agent.indexOf( " Maxthon " ) !=- 1 ){
                 Actual_Name += " (Maxthon) " ;
             }
             else if (Browser_Agent.indexOf( " Opera " ) !=- 1 ){
                 Actual_Name = " Opera " ;
                 var tempstart = Browser_Agent.indexOf( " Opera " );
                 var tempend = Browser_Agent.length;
                 Actual_Version = Browser_Agent.substring(tempstart + 6 ,tempend)
             }
         }
         else {
             Actual_Name = " Unknown Navigator "
             Actual_Version = " Unknown Version "
         }
         /* ------------------------------------------------------------------------------
         --Your Can Create new properties of navigator(Acutal_Name and Actual_Version) --
         --Userage:                                                                     --
         --1,Call This Function.                                                        --
         --2,use the property Like This:navigator.Actual_Name/navigator.Actual_Version;--
         ------------------------------------------------------------------------------ */
         navigator.Actual_Name = Actual_Name;
         navigator.Actual_Version = Actual_Version;
        
         /* ---------------------------------------------------------------------------
         --Or Made this a Class.                                                     --
         --Userage:                                                                  --
         --1,Create a instance of this object like this:var browser=new browserinfo;--
         --2,user this instance:browser.Version/browser.Name;                        --
         --------------------------------------------------------------------------- */
         this .Name = Actual_Name;
         this .Version = Actual_Version;
     }
     browserinfo();
    
     document.write( " 你使用的浏览器是: " + navigator.Actual_Name + " ,版本号: " + navigator.Actual_Version);