I have an extension that injects a script to a page that listens to certain events and then sends the data back to the background page.
The extension is restarted every n minutes, and so it happens that it injects the script again and again into that page.
Thus two or more exact same script copies are running at the same time and this behavior also leads to errors.
Is there are a way to stop executed scripts on a page, like a reverse of "chrome.tabs.executeScript" function, which I could call before injecting another instance of that script?
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I have an application in Node/Express that is exhibiting some strange (to me, at least) behavior. I am not sure why this happens, but as soon as I begin typing in the URL, the web page instantly comes up. All the logs start populating data and I have my home screen. This is on a local instance for now as I'm still trying to work out bugs related here. I believe these two may be inter-related, but I can't find any data online; perhaps I'm using the wrong search terms, but the long and the short of it is this:
I'm connected to a VM (CentOS7) and everything is run through AWS. I type in my IP:PORT (e.g. 12.34.56.78:9999). As SOON as I type the '1' in the URL, all the logs fire, running through all the scripts. Since I'm at my home page, I hit 'Enter' and is SUPPOSED to go through a redirect to an authorization page (e.g. 12.34.56.78:9999/auth). At that point we're running into my original post, identified above, but this question is simply an attempt to understand why my web page is being shown before I ever 'finish' the call by hitting the 'Enter' key. Is this normal behavior when an application is being accessed locally?
Because your browser is "smart" and guesses that you want to open that website and will therefore load it before you complete the url. That of course only happens if you have previously visited that site, otherwise the browser does not know the url yet. What logic the browser internally uses for this decision depends mostly on the browser and its settings, wether it factors in how recently you visited it or how often, or ...
If you actually want to browse that website when you finish typing the browser has already loaded the page and can instantly display it instead of now loading it and letting you wait a couple of seconds. If you decide you want to go to 123.com instead the browser simply discards the preloaded page and continues as normal.
My specific problem:
I have a content script that I inject into a page immediately after the DOM is complete ("run_at": "document_end"). After performing a very short task it should load a new website by adjusting window.location.href accordingly.
Now I've realized that there is another script (New Relic analytics) running that takes some time to be executed and prevents the new page from loading immediately.
The more general question:
a) Is my content script loaded before js scripts that are embedded in the site?
b) If this is the case, is there a way to stop the execution from other/following scripts and immediately load a new page with window.location.href?
Any help is very appreciated.
I'm writing a devtools Chrome extension with a dev panel. The devtools script can use chrome.devtools.inspectedWindow.reload to reload the page and run a script before other scripts run (in every frame in the inspected window). However, the injected script is no longer run for subsequent page reloads and newly created frames.
How can I inject a script into the inspected window that is run at the start of every subsequent page load in the inspected window?
I know I can use a content script that runs at document_start, but that would run the script at the start of each page load regardless of whether the dev panel is open - and the script is intensive, so I'd like to avoid running the script when it's not needed.
Could the devtools script somehow listen for the beginning of page loads in the inspected window and respond by running a script in the page's context?
One option that you can use to avoid running the script when it's not needed, as you have said, is programmatic injection. As discussed:
Inserting code into a page programmatically is useful when your JavaScript or CSS code shouldn't be injected into every single page that matches the pattern — for example, if you want a script to run only when the user clicks a browser action's icon.
To insert code into a page, you must have the following:
your extension must have cross-origin permissions for the page.
It also must be able to use the chrome.tabs module.
You can get both kinds of permission using the manifest file's permissions field.
Once you have permissions set up, you can inject JavaScript into a page by calling tabs.executeScript.
As also discussed in chrome.devtools.inspectedWindow in executing code in the inspected window, use the tabs.executeScript method unless you need the specific functionality that the eval method provides.
However in Communicating Between Extension Components, please note that:
The DevTools page can't call tabs.executeScript directly. To inject a content script from the DevTools page, you must retrieve the ID of the inspected window's tab using the inspectedWindow.tabId property and send a message to the background page. From the background page, call tabs.executeScript to inject the script.
You may go through the given documentations for more information and examples.
I have two scripts. I put them in the same namespace (the #namespace field).
I'd like them to interactive with another.
Specifically I want script A to set RunByDefault to 123. Have script B check if RunByDefault==123 or not and then have script A using a timeout or anything to call a function in script B.
How do I do this? I'd hate to merge the scripts.
The scripts cannot directly interact with each other and // #namespace is just to resolve script name conflicts. (That is, you can have 2 different scripts named "Link Remover", only if they have different namespaces.)
Separate scripts can swap information using:
Cookies -- works same-domain only
localStorage -- works same-domain only
Sending and receiving values via AJAX to a server that you control -- works cross-domain.
That's it.
Different running instances, of the same script, can swap information using GM_setValue() and GM_getValue(). This technique has the advantage of being cross-domain, easy, and invisible to the target web page(s).
See this working example of cross-tab communication in Tampermonkey.
On Chrome, and only Chrome, you might be able to use the non-standard FileSystem API to store data on a local file. But this would probably require the user to click for every transaction -- if it worked at all.
Another option is to write an extension (add-on) to act as a helper and do the file IO. You would interact with it via postMessage, usually.
In practice, I've never encountered a situation were it wasn't easier and cleaner to just merge any scripts that really need to share data.
Also, scripts cannot share code, but they can inject JS into the target page and both access that.
Finally, AFAICT, scripts always run sequentially, not in parallel. But you can control the execution order from the Manage User Scripts panel
I know there's a way for extensions and pages to communicate locally, but I need to send a message from an outside URL, have my Chrome Extension listen for it.
I have tried easyXDM in the background page, but it seems to stop listening after awhile, as if Google "turns off" the Javascript in the background page after awhile.
I think you may try some walk around and build a site with some specific data structure, and then implement a content script which will look for this specific that specific data structure, and when i finds one it can fetch the data you want to be passed to your extension.
Yes, you need a content script that communicates with the page using DOM Events.. Instructions on how to do that are here:
http://code.google.com/chrome/extensions/content_scripts.html#host-page-communication