CODEWITHSUNDEEP
apachebrowsermicrosoft-edgedeveloper-tools
ControlAltDel
ControlAltDel

Reputation: 35106

MS Edge: Opening the developer tools panel causes all http requests to occur twice

Using MS Edge and apache w/ php, I just discovered via access.log that when I have the JavaScript debug panel (i.e. developer panel) open, it is making every http call twice. When I closed this panel, it has fixed the issue of all insert statements getting called twice.

Question: Does this doubling of http calls happen on every / most browsers that I need to look out for, or is this something special/unique with MS Edge?

Upvotes: 0

Views: 597

Answers (1)

Andy Sterland
Andy Sterland

Reputation: 1936

I can't speak for all browsers and all developer tools. But, for IE and Edge the first time you open the tools and then open a JS file in the sources view it will try to request the file again. That request will be served from the local browser cache, sometimes not, depending on the cache settings for the file being requested.

The reason browser tools need to make this request is that browsers will often throw out the original source file as it doesn't need it to execute the page, as the source has been parsed it into something else that it can work with.

However, after you've opened the developer tools the browser will keep around sources in future navigations, either in the tools front end or elsewhere. Not keeping sources is an optimization for the first time use case, to save browsers keeping around source on the very low odds of the tool being used on any given navigation.

Of course some files are never cached by the browser and will need to be downloaded when requested by the tools, for example sourcemapped files.

In general any resources on your site that can be accessed by HTTP GET should be idempotent. That is, a GET shouldn't change the resource being requested (or generall the state of your site), so hopefully making additional requests shouldn't be an issue.

Upvotes: 1

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