How to programmatically empty browser cache?

Question

I am looking for a way to programmatically empty the browser cache. I am doing this because the application caches confidential data and I'd like to remove those when you press "log out". This would happen either via server or JavaScript. Of course, using the software on foreign/public computer is still discouraged as there are more dangers like key loggers that you just can't defeat on software level.

Answer 1

use html itself.There is one trick that can be used.The trick is to append a parameter/string to the file name in the script tag and change it when you file changes.

<script src="myfile.js?version=1.0.0"></script>

The browser interprets the whole string as the file path even though what comes after the "?" are parameters. So wat happens now is that next time when you update your file just change the number in the script tag on your website (Example <script src="myfile.js?version=1.0.1"></script>) and each users browser will see the file has changed and grab a new copy.

Answer 2

//The code below should be put in the "js" folder with the name "clear-browser-cache.js"

(function () {
    var process_scripts = false;
    var rep = /.*\?.*/,
    links = document.getElementsByTagName('link'),
    scripts = document.getElementsByTagName('script');
    var value = document.getElementsByName('clear-browser-cache');
    for (var i = 0; i < value.length; i++) {
        var val = value[i],
            outerHTML = val.outerHTML;
        var check = /.*value="true".*/;
        if (check.test(outerHTML)) {
            process_scripts = true;
        }
    }
    for (var i = 0; i < links.length; i++) {
        var link = links[i],
        href = link.href;
        if (rep.test(href)) {
            link.href = href + '&' + Date.now();
        }
        else {
            link.href = href + '?' + Date.now();
        }
    }
    if (process_scripts) {
        for (var i = 0; i < scripts.length; i++) {
            var script = scripts[i],
            src = script.src;
            if (src !== "") {
                if (rep.test(src)) {
                    script.src = src + '&' + Date.now();
                }
                else {
                    script.src = src + '?' + Date.now();
                }
            }
        }
    }
})();

At the end of the tah head, place the line at the code below

    < script name="clear-browser-cache" src='js/clear-browser-cache.js' value="true" >< /script >

Answer 3

You can now use Cache.delete()

Example:

let id = "your-cache-id";
// you can find the id by going to 
// application>storage>cache storage 
// (minus the page url at the end)
// in your chrome developer console 

caches.open(id)
.then(cache => cache.keys()
  .then(keys => {
    for (let key of keys) {
      cache.delete(key)
    }
  }));

Works on Chrome 40+, Firefox 39+, Opera 27+ and Edge.

Answer 4

The best idea is to make js file generation with name + some hash with version, if you do need to clear cache, just generate new files with new hash, this will trigger browser to load new files

Answer 5

Initially I tried various programmatic approach in my html, JS to clear browser cache. Nothing works on latest Chrome.

Finally, I ended up with .htaccess:

<IfModule mod_headers.c>
    Header set Cache-Control "no-cache, no-store, must-revalidate"
    Header set Pragma "no-cache"
    Header set Expires 0
</IfModule>

Tested in Chrome, Firefox, Opera

Reference: https://wp-mix.com/disable-caching-htaccess/

Answer 6

It's possible, you can simply use jQuery to substitute the 'meta tag' that references the cache status with an event handler / button, and then refresh, easy,

$('.button').click(function() {
    $.ajax({
        url: "",
        context: document.body,
        success: function(s,x){

            $('html[manifest=saveappoffline.appcache]').attr('content', '');
                $(this).html(s);
        }
    }); 
});

NOTE: This solution relies on the Application Cache that is implemented as part of the HTML 5 spec. It also requires server configuration to set up the App Cache manifest. It does not describe a method by which one can clear the 'traditional' browser cache via client- or server-side code, which is nigh impossible to do.