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phpjqueryajaxcodeigniterlong-polling

numbers behind the ajax long polling url /controller/method?_xxxx

I'm using codeigniter, I am curious about the get query for long polling I made

       function check_new_notif(){
            $.ajax({
                type:"GET",
                url:"/MAIN/AJAX/new_unotif",
                async:true,
                cache:false,
                datatype: "text",
                timeout:20000,

                success: function(dat){
                    show_new_notif(dat);
                    fetch_new_notif();
                    setTimeout(
                        check_new_notif,10000
                    );
                },
            error: function(XMLHttpRequest,textstatus,errorThrown){
                show_new_notif("error");
                setTimeout(
                    check_new_notif,10000
                );
            }
        });

what is the number used for? when my long polling request on server the links in firebug was like this

GET /MAIN/Ajax/notification?_=1466062273034

and the next call its /MAIN/Ajax/notification?_=1466062273035 ,incremented by one

Anyone know what this ?_=1466062273035 query means?

Thankies

Solution

  • When you set cache: false, it will append timestamp to your URL

    Doc: http://api.jquery.com/jquery.ajax/

    If set to false, it will force requested pages not to be cached by the browser. Note: Setting cache to false will only work correctly with HEAD and GET requests. It works by appending "_={timestamp}" to the GET parameters. The parameter is not needed for other types of requests, except in IE8 when a POST is made to a URL that has already been requested by a GET.