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
});
I'm creating a website that's going to have hundreds of pages. I want each page to be shareable on Facebook and Twitter. I've already created these buttons but I also want to have their respective share counters next to my share buttons. I don't want to use the standard Facebook method they provide because the coding looks bloated.
Right, so after doing some research, I found this example on codepen.
This looks exactly what I want - very simple!
However, I need some clarification and basic help with how this javascript code works:
var permalink = 'http://codepen.io';
var getTwitterCount = function () {
$.getJSON('http://urls.api.twitter.com/1/urls/count.json?
url='+permalink+'&callback=?', function(data){
var twitterShares = data.count;
$('.twitter .share-count').text(twitterShares);
});
};
getTwitterCount();
var getFacebookCount = function () {
$.getJSON('http://graph.facebook.com/?ids='+permalink+'&callback=?',
function(data){
var facebookShares = data[permalink].shares;
$('.facebook .share-count').text(facebookShares);
});
};
getFacebookCount();
This bit of code:
var permalink = 'http://codepen.io';
Does this have to be:
1) the url of the actual page I want shared, eg: http://www.example.com/page-1/
OR
2) Must this be the root of the domain name, eg: http://www.example.com/
?
Or am I missing something else?
If the answer is #1 above, then that means I have to include + edit this line for each page which isn't ideal because I have all my javascript code + plugins in ONE .js file to reduce http requests, so I'd prefer it that I don't have to add this javascript on-page for every page.
It would be the page that you want to share, but you could get around it without using a separate variable for each page by setting it to something like document.location.href for example?
tl;dr: A bookmarklet that opens in a new tab: random link (with specified multiple html-classes) from a specified domain and code that works with current logins. Thank you.
short version of butchered code:
javascript:
(
var % 20 site = domain.com
function() {
window.location.host == site
void(window.open(document.links[Math.floor(document.querySelectorAll("a.class1, a.class2"))].href, '_blank'))
}();
//beautified with: http://jsbeautifier.org/
To whom it may concern:
I have searched around for a while and even considered switching services but although some come close or are similar to my particular request, none have served to address everything the request entails.
Execute the script on a specific domain even when no page from said domain is currently open. If login authentication for attaining the information or data for execution is required, read or work in conjunction with existing session.
Fetch from a specific domain host, a random link out of all links on that domain with a certain html-class (or indeed otherwise) using preferably, css-selectors.
Open the results in a new tab.
From butchering such similarities, the result became something like this:
//bookmarklet
javascript:
//anonymous function+ wrapped code before execution
(
// function global variables for quick substitution
var %20 site = domain.com
function(){
//set domain for script execution
window.location.host == site
//open new tab for
void(window.open(document.links
//random link
[Math.floor
//with specific classes (elements found with css selectors)
(document.querySelectorAll("a.class1, a.class2"))
]//end random-query
.href,'_blank' //end page-open
)//end link-open
)//end "void"
}//end function defintion
//execute
();
//(tried) checked with:
//http://www.javascriptlint.com/online_lint.php
Lastly, i have attained at most, basic css knowledge. I apologise if this request has anybody headdesking, palming or otherwise in gtfo mode. It is only too sad there is apparently no tag for "Warning: I DIY-ed this stuff" in StackExchange. However, i still would like answers that go into a bit of depth of explaining why and what each correction and modification is.
Thank you presently, for your time and effort.
Theoretically, the following code should do what you want:
window.addEventListener('load', function ( ) {
var query = 'a.class1[href], a.class2[href]';
var candidates = document.querySelectorAll(query);
var choice = Math.floor(Math.random() * candidates.length);
window.open(candidates.item(choice).href, 'randomtab');
}, true);
window.location.href = 'http://domain.com';
But it doesn't, because the possibility to retain event listeners across a page unload could be abused and browsers protect you against such abuse.
Instead, you can manually load the domain of your choice and then click a simpler bookmarklet with the following code:
var query = 'a.class1[href], a.class2[href]';
var candidates = document.querySelectorAll(query);
var choice = Math.floor(Math.random() * candidates.length);
window.open(candidates.item(choice).href, 'randomtab');
You could wrap the above in javascript:(function ( ) { ... })(); and minify as before, but it already works if you just minify it and only slap a javascript: in front.
I understand your situation of being an absolute beginner and posting "DIY" code, but I'm still not going to explain step-by-step why this code works and yours doesn't. The first version of the code above is complex to explain to a beginner, and the list of issues with the code in the question is too long to discuss all of them. You'll be better off by studying more Javascript; a good resource with tutorials is MDN.
I'd like to inject a couple of local .js files into a webpage. I just mean client side, as in within my browser, I don't need anybody else accessing the page to be able to see it. I just need to take a .js file, and then make it so it's as if that file had been included in the page's html via a <script> tag all along.
It's okay if it takes a second after the page has loaded for the stuff in the local files to be available.
It's okay if I have to be at the computer to do this "by hand" with a console or something.
I've been trying to do this for two days, I've tried Greasemonkey, I've tried manually loading files using a JavaScript console. It amazes me that there isn't (apparently) an established way to do this, it seems like such a simple thing to want to do. I guess simple isn't the same thing as common, though.
If it helps, the reason why I want to do this is to run a chatbot on a JS-based chat client. Some of the bot's code is mixed into the pre-existing chat code -- for that, I have Fiddler intercepting requests to .../chat.js and replacing it with a local file. But I have two .js files which are "independant" of anything on the page itself. There aren't any .js files requested by the page that I can substitute them for, so I can't use Fiddler.
Since your already using a fiddler script, you can do something like this in the OnBeforeResponse(oSession: Session) function
if ( oSession.oResponse.headers.ExistsAndContains("Content-Type", "html") &&
oSession.hostname.Contains("MY.TargetSite.com") ) {
oSession.oResponse.headers.Add("DEBUG1_WE_EDITED_THIS", "HERE");
// Remove any compression or chunking
oSession.utilDecodeResponse();
var oBody = System.Text.Encoding.UTF8.GetString(oSession.responseBodyBytes);
// Find the end of the HEAD script, so you can inject script block there.
var oRegEx = oRegEx = /(<\/head>)/gi
// replace the head-close tag with new-script + head-close
oBody = oBody.replace(oRegEx, "<script type='text/javascript'>console.log('We injected it');</script></head>");
// Set the response body to the changed body string
oSession.utilSetResponseBody(oBody);
}
Working example for www.html5rocks.com :
if ( oSession.oResponse.headers.ExistsAndContains("Content-Type", "html") &&
oSession.hostname.Contains("html5rocks") ) { //goto html5rocks.com
oSession.oResponse.headers.Add("DEBUG1_WE_EDITED_THIS", "HERE");
oSession.utilDecodeResponse();
var oBody = System.Text.Encoding.UTF8.GetString(oSession.responseBodyBytes);
var oRegEx = oRegEx = /(<\/head>)/gi
oBody = oBody.replace(oRegEx, "<script type='text/javascript'>alert('We injected it')</script></head>");
oSession.utilSetResponseBody(oBody);
}
Note, you have to turn streaming off in fiddler : http://www.fiddler2.com/fiddler/help/streaming.asp and I assume you would need to decode HTTPS : http://www.fiddler2.com/fiddler/help/httpsdecryption.asp
I have been using fiddler script less and less, in favor of fiddler .Net Extensions - http://fiddler2.com/fiddler/dev/IFiddlerExtension.asp
If you are using Chrome then check out dotjs.
It will do exactly what you want!
How about just using jquery's jQuery.getScript() method?
http://api.jquery.com/jQuery.getScript/
save the normal html pages to the file system, add the js files manually by hand, and then use fiddler to intercept those calls so you get your version of the html file
How do I get the absolute or site-relative path for an included javascript file.
I know this can be done in PHP, (__file__, I think). Even for an included page, one can check the path (to the included file). Is there any way to have this self awareness in Javascript?
I know I can can get the page URL, but need to get the JS URL.
Eg. Javascript needs to modify the src of an image on the page. I know where the image is relative to the JavaScript file. I don't know where the Javascript is relative to the page.
<body>
<img id="img0" src="">
<script src="js/imgMaker/myscript.js"></script>
</body>
function fixPath(){
$$("#img0")[0].set('src','js/imgMaker/images/main.jpg');
}
Please do not tell me to restructure my function - the example is simplified to explain the need.
In the actual case, a Mootools class is being distributed and people can put it into whatever folder they want.
I would just read the src of the script element, but the class can be part of any number of javascript files, so I can't know what the element looks like.
JavaScript (not JScript) has no concept of file names. It was developed for Netscape back in the days. Therefore there is no __file__ feature or anything similar.
The closest you can come are these two possibilities:
What you already mentioned: Harvest all src attributes of all JS files and try to figure out which one is the right.
Make it a necessary option, that the path to the images must be set in the embedding HTML file. If not set, use a reasonable and well-documented default:
<script type="text/javascript">
var options = {
'path_to_images': '/static/images/' // defaults to '/js/img/'
};
</script>
Based on http://ejohn.org/blog/file-in-javascript/
(function(){
this.__defineGetter__("__FILE__", function() {
return (new Error).stack.split("\n")[2].split("#")[1].split(":").slice(0,-1).join(":");
});
})();
(function(){
this.__defineGetter__("__DIR__", function() {
return __FILE__.substring(0, __FILE__.lastIndexOf('/'));
});
})();
Then later
img.setAttribute('src', __DIR__ + '/' + file);
if you have folders:
/webroot
/images
/scripts
Then images would be an absolute path of /images/whatever.jpg and scripts would be an absolute path of /scripts/js.js
I'm using the following method to get the base URL and using it for loading the other prorotypes, maybe this is what you need. Lets say current script name is 'clone.js'.
/*
* get the base URL using current script
*/
var baseURL = '';
var myName = 'clone.js';
var myPattern = /(^|[\/\\])clone\.js(\?|$)/;
var scripts = document.getElementsByTagName("script");
for (var i = 0; i < scripts.length; i++) {
var src;
if (src = scripts[i].getAttribute("src")) {
if (src.match(myPattern)) {
baseURL = src.replace(myName, '');
break;
}
}
}
Var baseURL should contain what you need.
The path to the JS is irrelevant; links in the HTML file are always relative to the HTML file, even if you modify them from external JS.
[EDIT] If you need to build a path relative to the current web page, you can find its path in document.location.pathname. This path is relative to the web root but you should be able to find a known subpath and then work from there.
For example, for this page, it pathname would be /posts/1858724. You can look for posts and then build a relative path from there (for example posts/../images/smiley.png)
I know this question was asked awhile back but I have a similar situation to Sam's.
In my case, I have two reasons for the situation:
The user can access different sub-domains, each with its own index page.
The user can enter a password that causes index.php to adjust the paths.
Most of the references point to the same src locations for the scripts, but some do not. For instance, those at a different level of the tree would require a different path.
I addressed it by assigning an id to the index page's script tag. For example, the head might include...
<script id='scriptLocation' type='text/javascript' language='javascript' src='../scripts.test/script.js'></script>
My JavaScript is then able to read the path...
var myPath = document.getElementById("scriptLocation").src;
Found another approach, perhaps someone with more JS ninja can flush this out.
CSS stylesheet are able to find the node that called them using document.stylesheets.ownernode.
I could not find a similar call for javascript files.
But, in some cases, if one can include a CSS file together with the javascript, and give the first rule some unique identifier.
One can loop through all stylesheets till they find the one with the identifier [if(document.stylsheets[i].cssRules[0] == thisIs:myCSS)], than use ownerNode to get the path of that file, and assume the same for the JS.
Convoluted and not very useful, but its another approach - might trigger a better idea by someone.