Basically, I want to get all the opened tabs of the browser window, from within a tab, more specifically, in content script.
I tried chrome.tabs.query, it works in background script, but doesn't work in content script.
So my questions are:
Is there a way to do such work? Maybe an API that I wasn't aware of?
Or, can I dispatch an event from content script, then capture the event in background script, and vice versa?
Or, is it just impossible?
According to https://developer.chrome.com/extensions/content_scripts , a content script cannot access chrome.* APIs, except a few allowed ones but chrome.tabs is not among them
Exchanging messages with the parent script is possible, though, so this might be the way to do it. See https://developer.chrome.com/extensions/messaging
Related
I'm working on an extension that's supposed to use the content of the page to determine whether to show an interface to the user.
The ways to show an interface, if I'm correct, are using a browser action or a page action.
And neither can be triggered programmatically. But content scripts could be written to inject an equivalent GUI into the webpage.
So, does it make sense to modify the DOM using content-scripts to display an interface as a substitute for page action? It seems like an obvious work around to me, and I'm sure there are good reasons to not let page actions be triggered programmatically.
Well, modifying DOM must be done by only Content Scripts, as that is the reason they exist.
Want to fetch any data from current page, alter anything in the page, add new UI in the page - whatever, content script will help you do that.
It has nothing to do with Page script Or Browser Script.
YES, you can not programatically trigger page/browser action. It has to be done by explicit clicking.
But if you want to open a UI by clicking a chrome extension, then there is a popup js for that.
How can a Chrome extension alter the Google Calendar event editing UI?
I see that, for example, the Moxtra extension has managed to inject UI including a button just below the location. According to their YouTube video they added a button to fill out the event description although when I installed Moxtra this no longer seems to work.
Stepping back from this a bit, it occurs to me that editing the Google Calendar page seems like something that could easily get messed up by future changes to Google Calendar. Perhaps it is better to edit the event description from the extension's own UI? If so, how can that be done?
Thanks.
It can be done with content scripts and modification of the DOM.
They probably check Event edit page for specific selectors and try to insert their own elements in the page, if they found it.
So, if UI of Google Calendar will change, extensions like Moxtra will be probably also broken.
You are right about the edit of the description - it's safer. But you still need to get a description field and change a content of it. There is no 100% safe way to do it and don't break on the change of UI.
I am trying to develop a chrome extension which saves the url of webpages opened in all tabs and then load them whenever needed. Now I know content scripts, background scripts and popup.js. Content scripts mainly deal with the content of the loaded webpage and they have less chrome api interactions, background scripts are executed in an isolated environment and we can use all chrome api methods, popup.js is simply javascript that runs in context of popup.html.
Now here is my problem, I have a button in popup.html named "save" and on click of that button I want to save all the webpage urls opened in multiple tabs under one window. How can I do that?
Should I write a content or a background script?
Sorry for my noobish question. I am new to chrome api. Any help/suggestions?
Neither content script or background page is needed. You could do that just in popup.js, since popup page actually runs in the same context with extension.
In your popup.js, just call chrome.tabs.query to get tab info, including url (you would need to declare tabs permissions in manifest.json). If you want to specify window id, either use WINDOW_ID_CURRENT or retrieve it through other ways (depends on your logic)
chrome.tabs.query({ windowId: YOUR_WINDOW_ID }, (tabs) => {
tabs.forEach((tab) => console.log(tab.url));
});
I'm building a Google Chrome extension at the moment and I have a question about when to use an event page.
A quick look at the Chrome extension docs shows that Google really want its developers to use event pages, if possible.
My extension currently uses a background page, but I was wondering if I should switch to an event page?
This is what my extension does:
When matched with a particular website, it injects a script that adds buttons for the user to access extra functionality.
Most of this extra functionality consists of doing fairly computationally expensive operations on user-entered data - this is all done in the background page (it is all it does).
When a user wants to run these operations on their data they press a button and this passes a message, from the injected script to the background page, which then passes a message back containing the results of its operations.
Essentially, all the background page is doing is waiting for message passing from an injected script in one particular website and then running some operations. Since it doesn't need to be active all the time, this suggests that I should be using an event page.
Can anyone confirm if this would be a good idea for me? Or are there reasons why I should stick to a background page?
Allowing the background page to suspend (chrome.runtime.onSusend) is great, because it will free up system resources. The page will automatically be launched when a matching event happens (chrome.tab.onUpdated etc). I can't think of any compelling reason to use a persistent background page. You can always store any long term state in chrome.storage.local or indexedDb, etc.
I'm playing around with some stuff and trying to discern if when using a cross-domain iframe(post_message) if I can read the elements: div-tag p-tag etc of site within the iframe? I haven't seen any other posts on this, so hopefully someone can provide some insight.
postMessage allows you to communicate with a cooperating iframe. To use it, one window must send a message with postMessage and the other window must have an event listener listening for the message and it must process that message and do whatever you want done with it.
So, it is possible to use postMessage to retrieve content from an iframe, even a cross-origin iframe, but it requires that there be code in the iframe that can receive the message, understand what is being asked of it and do postMessage back to the original frame with the information that was requested.
So, this means that if you control both the window and iframe javascript, you can do what you ask, but if you don't control one of the two and they don't already have the right javascript code in them to fetch the data you want, then you can't get the job done with postMessage. All it does is deliver messages. The code to process those messages must be put there by the owner of that particular web page.