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How do you prevent Firefox and Safari from caching iframe content?
I have a simple webpage with an iframe to a page on a different site. Both the outer page and the inner page have HTTP response headers to prevent caching. When I click the "back" button in the browser, the outer page works properly, but no matter what, the browser always retrieves a cache of the iframed page. IE works just fine, but Firefox and Safari are giving me trouble.
My webpage looks something like this:
<html> <head><!-- stuff --></head> <body> <!-- stuff --> <iframe src="webpage2.html?var=xxx" /> <!-- stuff --> </body> </html> The var variable always changes. Although the URL of the iframe has changed (and thus, the browser should be making a new request to that page), the browser just fetches the cached content.
I've examined the HTTP requests and responses going back and forth, and I noticed that even if the outer page contains <iframe src="webpage2.html?var=222" />, the browser will still fetch webpage2.html?var=111.
Here's what I've tried so far:
I'm unable to do any JavaScript tricks because I'm blocked by the same-origin policy.
I'm running out of ideas. Does anyone know how to stop the browser from caching the iframed content?
I installed Fiddler2 as Daniel suggested to perform another test, and unfortunately, I am still getting the same results.
This is the test I performed:
Math.random() in JSP.With this test, I'm able to see exactly which pages are updating, and which pages are cached.
For a quick test, I load the page, navigate to another page, and then press "back." Here are the results:
Original Page:
Leaving page, then hitting back:
This shows that the inner page is being cached, even though the outer page is calling it with a different GET parameter in the URL. For some reason, the browser is ignoring the fact that the iframe is requesting a new URL; it simply loads the old one.
Sure enough, Fiddler confirms the same thing.
(I load the page.)
Outer page is called. HTML:
0.21300034290246206 <iframe src="http://ipv4.fiddler:1416/page1.aspx?var=0.21300034290246206" /> http://ipv4.fiddler:1416/page1.aspx?var=0.21300034290246206 is called.
(I navigate away from the page and then hit back.)
Outer page is called. HTML:
0.4470929019483644 <iframe src="http://ipv4.fiddler:1416/page1.aspx?var=0.4470929019483644" /> http://ipv4.fiddler:1416/page1.aspx?var=0.21300034290246206 is called.
Well, from this test, it looks as though the web browser isn't caching the page, but it's caching the URL of the iframe and then making a new request on that cached URL. However, I'm still stumped as to how to solve this issue.
Does anyone have any ideas on how to stop the web browser from caching iframe URLs?
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Loading the iframe content makes the browser cache the page in it, so that if you load it a second time later, the browser will simply fetch it from cache, unless your server is set up to always load the content afresh.
This is a bug in Firefox:
https://bugzilla.mozilla.org/show_bug.cgi?id=356558
Try this workaround:
<iframe src="webpage2.html?var=xxx" id="theframe"></iframe> <script> var _theframe = document.getElementById("theframe"); _theframe.contentWindow.location.href = _theframe.src; </script> If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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