How do I clear a browsers cache with JavaScript?
We deployed the latest JavaScript code but we are unable to get the latest JavaScript code.
Editorial Note: This question is semi-duplicated in the following places, and the answer in the first of the following questions is probably the best. This accepted answer is no longer the ideal solution.
How to force browser to reload cached CSS/JS files?
How can I force clients to refresh JavaScript files?
Dynamically reload local Javascript source / json data
Update: See location.reload() has no parameter for background on this nonstandard parameter and how Firefox is likely the only modern browser with support.
You can call window.location.reload(true) to reload the current page. It will ignore any cached items and retrieve new copies of the page, css, images, JavaScript, etc from the server. This doesn't clear the whole cache, but has the effect of clearing the cache for the page you are on.
However, your best strategy is to version the path or filename as mentioned in various other answers. In addition, see Revving Filenames: don’t use querystring for reasons not to use ?v=n as your versioning scheme.
You can't clear the cache with javascript.
A common way is to append the revision number or last updated timestamp to the file, like this:
myscript.123.js
or
myscript.js?updated=1234567890
Try changing the JavaScript file's src? From this:
<script language="JavaScript" src="js/myscript.js"></script>
To this:
<script language="JavaScript" src="js/myscript.js?n=1"></script>
This method should force your browser to load a new copy of the JS file.
Other than caching every hour, or every week, you may cache according to file data.
Example (in PHP):
<script src="js/my_script.js?v=<?=md5_file('js/my_script.js')?>"></script>
or even use file modification time:
<script src="js/my_script.js?v=<?=filemtime('js/my_script.js')?>"></script>
You can also force the code to be reloaded every hour, like this, in PHP :
<?php
echo '<script language="JavaScript" src="js/myscript.js?token='.date('YmdH').'">';
?>
or
<script type="text/javascript" src="js/myscript.js?v=<?php echo date('YmdHis'); ?>"></script>
window.location.reload(true) seems to have been deprecated by the HTML5 standard. One way to do this without using query strings is to use the Clear-Site-Data header, which seems to being standardized.
put this at the end of your template :
var scripts = document.getElementsByTagName('script');
var torefreshs = ['myscript.js', 'myscript2.js'] ; // list of js to be refresh
var key = 1; // change this key every time you want force a refresh
for(var i=0;i<scripts.length;i++){
for(var j=0;j<torefreshs.length;j++){
if(scripts[i].src && (scripts[i].src.indexOf(torefreshs[j]) > -1)){
new_src = scripts[i].src.replace(torefreshs[j],torefreshs[j] + 'k=' + key );
scripts[i].src = new_src; // change src in order to refresh js
}
}
}
try using this
<script language="JavaScript" src="js/myscript.js"></script>
To this:
<script language="JavaScript" src="js/myscript.js?n=1"></script>
Here's a snippet of what I'm using for my latest project.
From the controller:
if ( IS_DEV ) {
$this->view->cacheBust = microtime(true);
} else {
$this->view->cacheBust = file_exists($versionFile)
// The version file exists, encode it
? urlencode( file_get_contents($versionFile) )
// Use today's year and week number to still have caching and busting
: date("YW");
}
From the view:
<script type="text/javascript" src="/javascript/somefile.js?v=<?= $this->cacheBust; ?>"></script>
<link rel="stylesheet" type="text/css" href="/css/layout.css?v=<?= $this->cacheBust; ?>">
Our publishing process generates a file with the revision number of the current build. This works by URL encoding that file and using that as a cache buster. As a fail-over, if that file doesn't exist, the year and week number are used so that caching still works, and it will be refreshed at least once a week.
Also, this provides cache busting for every page load while in the development environment so that developers don't have to worry with clearing the cache for any resources (javascript, css, ajax calls, etc).
or you can just read js file by server with file_get_contets and then put in echo in the header the js contents
Maybe "clearing cache" is not as easy as it should be. Instead of clearing cache on my browsers, I realized that "touching" the file will actually change the date of the source file cached on the server (Tested on Edge, Chrome and Firefox) and most browsers will automatically download the most current fresh copy of whats on your server (code, graphics any multimedia too). I suggest you just copy the most current scripts on the server and "do the touch thing" solution before your program runs, so it will change the date of all your problem files to a most current date and time, then it downloads a fresh copy to your browser:
<?php
touch('/www/control/file1.js');
touch('/www/control/file2.js');
touch('/www/control/file2.js');
?>
...the rest of your program...
It took me some time to resolve this issue (as many browsers act differently to different commands, but they all check time of files and compare to your downloaded copy in your browser, if different date and time, will do the refresh), If you can't go the supposed right way, there is always another usable and better solution to it. Best Regards and happy camping.
I had some troubles with the code suggested by yboussard. The inner j loop didn't work. Here is the modified code that I use with success.
function reloadScripts(toRefreshList/* list of js to be refresh */, key /* change this key every time you want force a refresh */) {
var scripts = document.getElementsByTagName('script');
for(var i = 0; i < scripts.length; i++) {
var aScript = scripts[i];
for(var j = 0; j < toRefreshList.length; j++) {
var toRefresh = toRefreshList[j];
if(aScript.src && (aScript.src.indexOf(toRefresh) > -1)) {
new_src = aScript.src.replace(toRefresh, toRefresh + '?k=' + key);
// console.log('Force refresh on cached script files. From: ' + aScript.src + ' to ' + new_src)
aScript.src = new_src;
}
}
}
}
If you are using php can do:
<script src="js/myscript.js?rev=<?php echo time();?>"
type="text/javascript"></script>
Please do not give incorrect information.
Cache api is a diferent type of cache from http cache
HTTP cache is fired when the server sends the correct headers, you can't access with javasvipt.
Cache api in the other hand is fired when you want, it is usefull when working with service worker so you can intersect request and answer it from this type of cache
see:ilustration 1 ilustration 2 course
You could use these techiques to have always a fresh content on your users:
Use location.reload(true) this does not work for me, so I wouldn't recomend it.
Use Cache api in order to save into the cache and intersect the
request with service worker, be carefull with this one because
if the server has sent the cache headers for the files you want
to refresh, the browser will answer from the HTTP cache first, and if it does not find it, then it will go to the network, so you could end up with and old file
Change the url from you stactics files, my recomendation is you should name it with the change of your files content, I use md5 and then convert it to string and url friendly, and the md5 will change with the content of the file, there you can freely send HTTP cache headers long enough
I would recomend the third one see
You can also disable browser caching with meta HTML tags just put html tags in the head section to avoid the web page to be cached while you are coding/testing and when you are done you can remove the meta tags.
(in the head section)
<meta http-equiv="Cache-Control" content="no-cache, no-store, must-revalidate" />
<meta http-equiv="Pragma" content="no-cache" />
<meta http-equiv="Expires" content="0"/>
Refresh your page after pasting this in the head and should refresh the new javascript code too.
This link will give you other options if you need them
http://cristian.sulea.net/blog/disable-browser-caching-with-meta-html-tags/
or you can just create a button like so
<button type="button" onclick="location.reload(true)">Refresh</button>
it refreshes and avoid caching but it will be there on your page till you finish testing, then you can take it off. Fist option is best I thing.
I tend to version my framework then apply the version number to script and style paths
<cfset fw.version = '001' />
<script src="/scripts/#fw.version#/foo.js"/>
Cache.delete() can be used for new chrome, firefox and opera.
I found a solution to this problem recently. In my case, I was trying to update an html element using javascript; I had been using XHR to update text based on data retrieved from a GET request. Although the XHR request happened frequently, the cached HTML data remained frustratingly the same.
Recently, I discovered a cache busting method in the fetch api. The fetch api replaces XHR, and it is super simple to use. Here's an example:
async function updateHTMLElement(t) {
let res = await fetch(url, {cache: "no-store"});
if(res.ok){
let myTxt = await res.text();
document.getElementById('myElement').innerHTML = myTxt;
}
}
Notice that {cache: "no-store"} argument? This causes the browser to bust the cache for that element, so that new data gets loaded properly. My goodness, this was a godsend for me. I hope this is helpful for you, too.
Tangentially, to bust the cache for an image that gets updated on the server side, but keeps the same src attribute, the simplest and oldest method is to simply use Date.now(), and append that number as a url variable to the src attribute for that image. This works reliably for images, but not for HTML elements. But between these two techniques, you can update any info you need to now :-)
Most of the right answers are already mentioned in this topic. However I want to add link to the one article which is the best one I was able to read.
https://www.fastly.com/blog/clearing-cache-browser
As far as I can see the most suitable solution is:
POST in an iframe. Next is a small subtract from the suggested post:
=============
const ifr = document.createElement('iframe');
ifr.name = ifr.id = 'ifr_'+Date.now();
document.body.appendChild(ifr);
const form = document.createElement('form');
form.method = "POST";
form.target = ifr.name;
form.action = ‘/thing/stuck/in/cache’;
document.body.appendChild(form);
form.submit();
There’s a few obvious side effects: this will create a browser history entry, and is subject to the same issues of non-caching of the response. But it escapes the preflight requirements that exist for fetch, and since it’s a navigation, browsers that split caches will be clearing the right one.
This one almost nails it. Firefox will hold on to the stuck object for cross-origin resources but only for subsequent fetches. Every browser will invalidate the navigation cache for the object, both for same and cross origin resources.
==============================
We tried many things but that one works pretty well. The only issue is there you need to be able to bring this script somehow to end user page so you are able to reset cache. We were lucky in our particular case.
window.parent.caches.delete("call")
close and open the browser after executing the code in console.
Cause browser cache same link, you should add a random number end of the url.
new Date().getTime() generate a different number.
Just add new Date().getTime() end of link as like
call
'https://stackoverflow.com/questions.php?' + new Date().getTime()
Output: https://stackoverflow.com/questions.php?1571737901173
I've solved this issue by using
ETag
Etags are similar to fingerprints, and if the resource at a given URL changes, a new Etag value must be generated. A comparison of them can determine whether two representations of a resource are the same.
Ref: https://developer.mozilla.org/en-US/docs/Web/API/Cache/delete
Cache.delete()
Method
Syntax:
cache.delete(request, {options}).then(function(found) {
// your cache entry has been deleted if found
});
When I click on a certain link the server writes if I have done it by stating either true or false in a text file...
Just like this:
{"needs_click":false,"has_clicked":false,"sites":[{"id":2134,"name":"testing","has_clicked":false,"click_url":"http://testing.com?siteid=5433"}]}
Now what I have done is uploaded a text file to my FTP already and changed all the false results into true like this:
{"needs_click":true,"has_clicked":true,"sites":[{"id":2134,"name":"testing","has_clicked":true,"click_url":"http://testing.com?siteid=5433"}]}
Now in one of the JavaScript files attached to the source code there is the variable at the top directing to the text file I just need to know how to make my browser read the spoofed link I created instead of the original.
I need to change the variables:
var API_VERSION = 0.1;
var API_URL = "http://api.testwebsite.com/" + API_VERSION + "/";
To:
var API_VERSION = 0.1;
var API_URL = "http://api.testwebsite2.com/" + API_VERSION + "/";
So it reads the other text file stating all the true options instead of the original... any suggestions?
What if you used a personal proxy to shape the query? Something like Charles proxy could work. In any case you will need to get in between the browser and server to do this sort of thing.
Alternatively you could try to rewrite entire JavaScript (ie. remove the original from source before loading and inject your own with the url fixed, you might be able to get away with a replace on the original). I don't know how feasible this is, though, as I don't know internals of Greasemonkey well enough. But this might be something to explore.
Was impossible, at the time I was very new to programming and limitations on what I could and could not do.
I'm trying to do this by using a Tampermonkey Script. However I'm open to new approaches...
What I want to do is extract some data (data-video), from a specific <div>. However this data is not available under the HTML code of the page, but it's available under Dev Tools -> Resources and then on Frames.
Anyone knows if it's possible to get that information available under DevTools? And how can I do that?
Comparative between the two pages can be found here: "Original HTML PAGE" and "HTML PAGE under DevTools"
On the first hyperlink the id=video-canvas cannot be seen, however it's on the <object type="application/x-shockwave-flash(...)
As you state in your question the data you're looking for is available in DevTools under the "Resources" tab in the "Frames" folder. What you are looking at there is the Source HTML, similar to View Source.
The code you want, is what is getting replaced. It appears the site is using the JW Player Plugin, which is replacing the <div id="video-canvas"> with the appropriate HTML for the device / browser detected to play the video. With all of my browsers on my Mac, they are being forced to use the Flash, even when it's disabled. When using my iPhone, which can't play flash , and inspecting the page it uses JW's own custom video element. It appears that it must be storing the file location in memory since it is not in the generated markup.
I am able to run through the console in the dev tools and access their JS class. It appears i can call jwplayer._tracker , which has an object b . Object b has an object AlWv3iHmEeOzwBIxOUCPzg This object seems to be consistent each time i check between different browsers, you can use the for loop inmy first example to get the correct value but tirmming it down to .b Following that object is e and in e is the object http://i.n.jwpltx.com/v1.... really long string that appears to contain a url, so it will need to parsed.
So to get the HTML string i ran
for ( var loc in jwplayer._tracker.b.AlWv3iHmEeOzwBIxOUCPzg.e){
loc
}
so if we put that in a function to parse the string and return a value
function getSubURL(){
var initURL;
for ( var loc in jwplayer._tracker.b.AlWv3iHmEeOzwBIxOUCPzg.e){
initURL = loc;
}
//look for 'mp4:' this is in front of the file path
var start = initURL.indexOf("mp4%3A");
//look for the .mp4 for the end of the file name
var stop = initURL.indexOf(".mp4");
//grab the string between
//start+6 to remove characters used to find it
//and stop+4 to include characters used to find it
var subPath = (initURL.substring((start+6),(stop+4))).split("%2F").join("/");
return subPath;
}
//and run it
getSubURL();
it will return ciencia/astronomia/fimsol.mp4
you can run this from your console, but I am unaware of how you can use this in Tamper Monkey, but i think it gets ya a lot closer to what you wanted.
This is the approach I've used to solve my problem... I couldn't grab the code I want under Dev Tools, but I find a way to get the data from jwplayer with the function getPlaylistItem. And this is how I get the url filename of each video:
function getFilename(filename) {
var filename;
if(jwplayer().getPlaylistItem){
filename = jwplayer().getPlaylistItem()['file'];
}
else{
return filename;
}
filename = filename.substring(filename.indexOf("/mp4:") + 5);
return filename;
}
Can anybody explain how the following javascript variables:
document.referrer
document.location.href
or the http REFERRER header, could come to be 'javascript:window["contents"]' ?
Not only do I not understand how they could be set to a javascript uri - but window.contents isn't a standard DOM attribute in any browser that I know of... (It is window["contents"], not window["content"])
I believe I found the solution to this..
There are some javascripts in the wild which seem to create iframes using code (something) like this:
var contents = '<html>......</html>';
var ifr = document.createElement('iframe');
ifr.contentWindow.open();
ifr.contentWindow.write(contents);
some particular combination of this sometimes ends up specifying either the href of the iframe , or the referrer, as "javascript:window['contents']" - i.e. the javascript variable which temporarily holds the page data.
(still not completely finalized on the details, but that's the basic idea)
I am trying to redirect to a different page in IE9 (9.0.3).
When I try to get/set document.location, or document.location.href, or window.location/window.location.href, I'm unable to do so. It fails without giving any errors.
I've tried to check whether the document and windows objects are set, and they are, so I have no idea why the location object is "missing".
I tried getting the document.URL and that works fine, but it's read-only.
Anyone know what the problem is or how to achieve this in a cross-browser way?
I was also experiencing the same problem but found that adding
window.event.returnValue = false;
above line in the javascript before the redirection resolved the problem.
See this: http://social.msdn.microsoft.com/Forums/en/iewebdevelopment/thread/c864ae63-66f6-4656-bcae-86b0018d70c9
Apparently it's a caching bug, you can solve it by appending a timestamp to the destination URL (that is, using a "unique" URL every time).
Perhaps your IE9 has some security restrictions in place that prevent JavaScript from directing URL's. window.location.href = "" should work normally on IE9.
Cache may be the reason, try:
location.href='something.php?tmp=' + Date.parse(new Date())
Hope it helps
You should use an absolute URL:
var url = '/section/page/';
var host = window.location.hostname;
window.location = 'http://' + host + url;
Where url is the relative path to your page.