Stop Javascript and HTML from Loading From Cache

Question

I am building a single page javascript app and when the application starts I use a single javascript file to load every other file I need on the fly. When I hit refresh, according to firebug, my HTML page as well as javascript pages will load with a 304 Not Modified Error and my javascript stops working.

I understand this is due to browser caching, but how can I avoid this? I load the initial HTML page with a single script call

<script src="js/config.js" type="text/javascript"></script>

and then continue to load the rest dynamically from within that script

window.onload = function () {
    var scripts = ['http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.7.1.min.js', 'js/core.js', 'js/sandbox.js']; //Application scripts
    var loaded = 0;
    //Callback is executed after all scripts have been loaded.
    var callback = function () {
        if (loaded + 1 == scripts.length) {
            //Create Modules
            CORE.loader("js/modules/Login.js", function () {
                CORE.createModule('loginForm', Login);
            });

            //Create HTML bindings.
            CORE.createBinding('appContainer', '#Login', 'login.html');
            CORE.bindHTML(window.location.hash); //Loads hash based page on startup
        } else {
            loaded++;
            loadScript(scripts[loaded], callback);
        }
    };

    loadScript(scripts[0], callback);

    function loadScript(scriptSrc, callback) {
        var script = document.createElement('script');
        script.type = 'text/javascript';
        script.async = true;
        script.src = scripts[loaded];

        if (script.readyState) {
            script.onreadystatechange = function () {
                if (script.readyState == 'loaded' || script.readyState == 'complete') {
                    script.onreadystatechange = null;
                    callback();
                }
            };
        } else {
            script.onload = function () {
                callback();
            };
        }

        document.getElementsByTagName('head')[0].appendChild(script);
    }
};

I know that Gmail uses cookies to prevent this. Does anyone have any idea how to take that approach? Should I set the cookie on the server and then check it with JS on each page load/refresh and use something like window.location.refresh() if the cookie tells me the page is loaded from cache?

Answer 1

I would suggest to use Javascript to generate a random number using Math.random multiply it and then Math.floor to return the integer of it. Then, I would add this number to the URL as a variable. Since the number changes during every page load, the file should never be cached.

<script>
  var url="yourscript.js";
  var extra="?t=";
  var randomNum = String((Math.floor(Math.random() * 200000000000000)));
  document.getElementById('myScript').src = url+extra+randomNum;
</script>
<script id="myScript"></script>