I am trying to implement a hard limit on a how long a web page can load via a Chrome extension. I have seen a number of implementations that suggest using a content script to call window.stop(), but in some cases the browser is never going to execute that JavaScript because it's still attempting to load a page that is going to time out. An example of such a site is http://blackhole.webpagetest.org.
At a very basic level, I need the extension to be able to hit the "Stop" button in the browser after a specified amount of time.
Any suggestions on how to accomplish this in Chrome?
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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.
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.
When a site gets stuck in chrome with the 'loading www.site.com' status, Is there anyway to know which of the elements on the DOM is delaying the load? for example, it can be an external js file or image that is taking long time to load. I tried using the network tab in the DeveloperTools, but it only shows the elements already loaded and the time they took. I couldn't find a way to see which element is stuck.
I found a way that I'm not sure it works in all cases, but it did for me. I used the Timeline tab (now shown in the Performance tab), it's one of the tabs in Chrome Dev Tools.
Open Chrome Developer tools (F12 or CMD + Alt + I in Mac) and click the Performance tab
Make sure you drag the grey timeline bar all the way to the right, you want to see the most recent section of events so you can find what's getting stuck:
Check just down below the records sidebar. If you don't see this like in the capture below, try toggling the icons, there are different view modes. Now, going all the way down I found these. It doesn't look like that's going well. Obviously some kind of infinite loop in some random code:
I couldn't find out if it was an extension itself or some other bit of code. Clicking through I only could find // Copyright 2014 The Chromium Authors. All rights reserved..
Checking in Incognito mode clear of extensions, the website loads just fine.
I'd also advise to check the Console tab to see if there are were any errors that might cause the infinite loading thing. You'll often find clues there.
I've been working on a new website and practicing my JS/jQuery/AJaxy skills. Last night I wanted to take a look at how long the page was taking to render and see if there were any areas I could clean up to increase speed. While the page loads in about 200 - 300 ms every time, I'm seeing a large amount of blank space between resource loads under the network inspector.
http://i.imgur.com/7ng6m.jpg
Has anyone else seen this or know what I can do to minimize that time (talking about the blank space between like the html and the first css file)?
Quite possibly it is caused by the extensions you have installed. AdBlock, LastPass and Google quick scroll took altogether about 200 ms on my machine.
Unfortunately, these extensions are invoked on every site and block loading the additional resources.
Try it with out of the box browser setup, the loading time will increase tremendously.
You've got a bunch of images loaded just after the page has been loaded (the load and DOMContentLoaded events have fired - the blue and red vertical lines across the Timeline). I can see that the images are loaded by the JQuery library (the Initiator column), perhaps to build a gallery or something.
So, the case is that JQuery loads the images after the page load, presumably in the onload handler (this can look like $(document).ready(handler) in your code, but other options are possible, too).
The delay between the initial page load and requesting the first resources is almost certainly caused by Chrome extensions. To find the culprit: Record a timeline in the Timeline tab in Chrome Developer Tools; Identify the scripts that are running during the Parse HTML phase; Work out which extensions they're from.
To record a timeline:
Open the timeline tab and click record.
Reload the page and then stop the recording. (A couple of seconds should be enough.)
To find the culprit:
Find the first main Parse HTML block on the timeline. On the row below you will probably see one or more Evaluate Script blocks. These are the culprits.
Click on one of the Evaluate Script blocks and find the script name in the bottom pane. Mouse-over the script name. The tooltip will have the URL of the script, which should be of the form chrome-extension://{long_identifier}/{path}
Memorise the first few letters of the identifier and search for it in the chrome://extensions/ page. This tells you which extension is causing the problem. Try disabling it - you should see a difference.
Repeat for the other Evaluate Script blocks.
In my case, I have 20 extensions installed but only two were causing a delay: LastPass and Fauxbar. I've chosen to leave them enabled because for me the productivity benefit of these extensions outweighs the downside of the added latency.
Problem context:
I have a C++ program and a web presence. Currently the way things are working I have made a control panel with javascript and html. And it send commands via an unimportant communication medium to control things or get information from the C++ program.
Now, when the C++ program launches, I'm making it run a
ShellExecute(NULL, "open", addressBuffer," --new-window", NULL, SW_NORMAL);
This is a way of launching the default browser with the given address. The addressBuffer in this case points to an intermediate HTML file that quickly turns around and uses the
window.open()
in Javascript to open the final popup, then closes itself.
The result is the user now has the popup control panel that I want them to have but the user's main browser window also gets given focus, un-minimized, and placed on a different tab than the one they had selected. (Basically pops up out of nowhere and selects a another tab)
Problem:
I'm looking for a way to launch a Chrome popup, without disturbing a previously open browser window. Any ideas or solutions would be very helpful.
Lastly, it's worth noting that the " --new-window" from the code above doesn't actually open a new window like you would expect. In this case it's actually doing nothing... If it did work, none of this would really be an issue.
I know this is wordy so thanks in advance for you time!
-Michael
Alright, I came up with a solution.
Something about how ShellExecute processes it's commands was preventing the command line args to be passed in correctly.
My work-around includes grabbing the path to Chrome from the registry,
HKET_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\chrome.exe
Then simply doing a system() command with the chrome path "--new-window" and the web path.
Then I let the intermediate html page open it's popup and close itself.
Tada done.
Thanks.