I'm trying to debug a problem that only occurs when I access a mobile website from a mobile browser. I strongly suspect that the root cause of the problem is due to caching that occurs when you access the same page several times.
I can reproduce the problem consistently when I access the page from my Android phone, but if I use a desktop browser the problem never occurs.
Because I can't use any developer tools on my Android phone, I really need to reproduce the problem from a desktop browser, so that I've some way of debugging into it. I've already tried using both Firefox and Chrome with an appropriate setting of the User-Agent header (so that the mobile version of the site is displayed), but that doesn't work.
Is there a better way to emulate the behaviour of a mobile browser from the desktop, in a manner that allows the client-side code can be debugged? FWIW, I'm fairly confident that I could also reproduce the problem on an iPhone, but don't have one available.
You can use a debugger on your phone, using chrome debugger.
Nowadays, you can just navigate to chrome://inspect/#devices after plugging your device in.
If that doesn't work, you can use the old method:
Connect your mobile device to the host using a USB cable
On the mobile device, launch Chrome. Open Settings > Advanced > Developer tools and check the Enable USB Web debugging option
Issue the following command in the console on your host machine to enable port forwarding:
adb forward tcp:9222 localabstract:chrome_devtools_remote
Open desktop Chrome and navigate to localhost:9222
Choose the page you need to debug
You can now start debugging and profiling mobile content in the Developer Tools on your desktop
Related
This question is related to my earlier question How to Debug Javascript in IOS Action App Extension. Basically, I am developing an mobile safari extension, and part of the work is to develop a javascript (operating on top of "document" provided by mobile safari) to run inside the app extension.
However, I have not found a way to debug a javascript file inside an app extension. Now, I am trying to ask the question a bit differently - given mobile safari on a page, can I somehow run an external javascript on that page and debug this external javascript? I suppose that Safari Web Inspector could help with that? Thanks.
(This is a slightly customized answer from your other question)
The official documentation for this is [here][1].
It's not too hard, although recently I've had an issue with the page showing up when connected to the iOS simulator. In that case I just ended up using my phone directly. (Apparently you need to start desktop Safari after the iOS Simulator has started to inspect "remote" Simulator sessions)
Ensure that on the device Settings->Safari->Advanced->Web Inspector is on.
(Make sure you've Trusted the computer from the device)
Start MobileSafari on your device.
Start Safari on your desktop, make sure Show Develop menu in menu bar is on in Preferences.
In the Develop menu you will see your device name, say 'BSharer's iPhone'.
select the page name underneath your device name, say 'en.m.wikipedia.org - Wikipedia'.
You are now debugging that device's page on your desktop. The developer page will open and you can debug as if it was running on the desktop machine. You should now see all the JavaScript that is available to that page and set breakpoints.
(The app extension requires the debugger; statement because we don't see the javascript files injected by the app extension. You can still use the debugger statement but it's not usually necessary.)
I am creating a purely browser based app - HTML and JavaScript.
I do not have an Android IDE installed (nor one for iOS) - and would prefer not to have to install one and perform remote debugging.
Developing on my PC, I use the Chrome browser and the developer tools to view the JavaScript console in order to debug.
How can I do that on an Android tablet (or, later, iOS)? I prefer a purely browser based solution, but could accept an Android/iOS based app.
Try https://github.com/liriliri/eruda
All you need to do is add this snippet on top of the page:
<script src="https://cdn.jsdelivr.net/npm/eruda"></script>
<script>eruda.init();</script>
And you get an interactive set of developer tools similar to those in Chrome and Firefox. Here's a screenshot:
Just released for iOS, Chrome 73 now supports the option to see console.log.
If you’re a website developer, you can now view JavaScript console
messages. Navigate to chrome://inspect to enable, then perform desired
actions in another tab. Switch back to the same chrome://inspect tab
to view any printed JavaScript console logs.
see here in "What's New" section or in "version history" 73.x version.
For Android you can use remote debugging through chrome as described here
I'll summarize/rewrite the steps (for browser based debugging) here in case the link ever goes down.
Requirements:
For browser tabs: Android 4.0+ and Chrome for Android
A USB cable to plug in your Android device
Chrome 32 or later installed on your development machine
Set up:
Enable USB debugging on your device.
Navigate to chrome://inspect/#devices on your desktop Chrome browser. (Alternatively, to get to the same screen, you can select Chrome menu > Tools > Inspect Devices)
After connecting, you may see an alert on the device requesting permission for USB debugging from your computer. Tap OK
Chrome should now display the connected device
Open up chrome on your Android device and navigate to the page you want to debug/inspect. The page should show up on your desktop browser and you should be able to inspect it.
If for some reason you have an older version of chrome and cannot upgrade. There is a plugin that you can install to accomplish the same thing.
I was searching for a while for something like this. Firebug Lite used to be an option but has been abandoned. Before discovering eruda (as mentioned elsewhere in this thread), I developed my own open source console. It's pretty light on features, but it does the main things - capture JS errors, and allow you to run commands to inspect variables and object on your page.
Here's a demo:
It's activated by just placing this script tag on your page:
<script src="https://cdn.jsdelivr.net/gh/SimonEast/MiniConsoleJS#main/console.js"></script>
Open source, GPL licence. Available at: https://github.com/SimonEast/MiniConsoleJS/
new iOS 6 feature is, that you can debug html and javascript running on device or simulator in desktop safari. I suppose, that this feature is based on Webkit Remote Debugging Protocol.
How can I connect to webkit running on iPhone without desktop Safari?
I can do this for mobile Chrome running on Android using websockets, but how can I do that for iOS devices?
The ios-webkit-debug-proxy project (from Google!) does this.
You want to look at this code https://github.com/leftlogic/remote-debug/tree/master/safari - although it fails when it actually comes to RPC calls that use __rpc_forwardSocketData.
If you've got any ideas why several of us are interested!
You need to open up the iPhone Simulator and browse to a website.
Then open Safari and choose "Develop" from the menubar. There is a the option called "iPhone Simulator".
If you hover over this you can see all of the open websites of the simulator.
This gives you the same inspector Safari uses. You can even see hovered elements in the iPhone Simulator.
I am looking for tools that allow to perform profiling of websites on mobile devices similar to what Firebug and Chrome dev tools allow to do.
I have used Weinre quite extensive. While it is an awesome tool to use with real devices, it does not provide facilities for run-time profiling.
Has anyone heard or used any tools that allow to do so?
Here is a great list of mobile performance testing tools from Steve Sauders (the guy that wrote the book "High Performance Web Sites"):
Mobile Perf bookmarklet - An uber bookmarklet with links to multiple other bookmarklets useful for mobile (mine)
Jdrop - JSON in the cloud for gathering data on mobile devices (mine)
Mobitest - Connects WebPagetest.org to Android and iPhone devices (Blaze.io)
pcapperf - Get HTTP waterfall charts from your mobile device connected to a wifi hotspot, blog post (open source)
WebWait - The only way I can think of to measure page load times on real devices over 3G - load URL in an iframe (Michael Mahemoff)
weinre - Web Inspector Remote, very cool way to debug your mobile device remotely (Patrick Mueller)
Reflow Timer - Bookmarklet to measure reflow time (Lindsey Simon, open source)
Favelet Suite - An uber bookmarklet, tons of features! (slayeroffice)
Source: http://stevesouders.com/mobileperf/
UPDATE:
You can use Chrome Devtools with an Android device and you can use Safari Devtools on a Mac with an iOS device.
Chrome: https://developer.chrome.com/devtools/docs/remote-debugging
Safari: https://blog.idrsolutions.com/2015/02/remote-debugging-ios-safari-on-os-x-windows-and-linux/
You connect via USB
You can profile/debug/inspect Chrome-on-Android using the desktop Chrome developer tools interface:
https://developers.google.com/chrome/mobile/docs/debugging
It'll require Chrome, an Android device able to run the Chrome app, and a USB cable.
Its a bit annoying to setup, because you have to install and use the ADB console command, but once its working, you'll have the full chrome developer tools interface available for debugging mobile.
Additionally, Google appears to be supporting this feature for new dev-tool Crhome extensions like PageSpeed.
For iOS debugging on Mac, you can use desktop Safari:
connect your device with a USB cable
start the app on the device
launch Safari on your computer
go to Develop -> device_name -> file_name.html
(if the Develop menu is not available for you, then go to Edit menu > Preferences... > Advanced tab and check Show Develop menu in menu bar checkbox)
It launches standard Safari web inspector, which is pretty similar to Chrome Developer Tools, although somewhat limited compared to it.
I'm developing a JavaScript application that needs to run on the Google Android Phone OS. Is there a way to enable the JavaScript Error/Debug console within Safari on either the Android Emulator or an actual device? If so any instructions on how to do so would be appreciated.
It looks like, with the Android 2.0.1 SDK you'll need to filter on "browser" instead of "WebCore"
A quick Google turns up this blog post (posted after you asked your question), that should at least let you see any Javascript errors via the Android Debug Bridge using the command:
adb logcat WebCore:V *:S
Not quite the same as a full debug console though.
On Android write about:debug on the address line when the current page is the page you want to debug. you will get access to the console.
I know your question is about Safari, but you might want to look into using Chrome instead. You can now use Chrome's desktop developer tools to debug and profile apps on your Android device.
Here's how:
On Android Chrome, go to settings -> Developer tools and check "Enable USB Web debugging"
On the desktop, run adb forward tcp:9222 localabstract:chrome_devtools_remote
Now on Desktop Chrome, navigate to localhost:9222.
You should see a list of the pages you have open on your phone. Click the one you want to debug/profile.
Detailed instructions are here
I have discovered that you can get this debugging information on the phone itself, without needingn to use adb or plug it into a computer, just download a log viewer.
Check the link for more info.
You can view the log and much more with weinre
From the Weinre docs
weinre is a debugger for web pages, like FireBug (for FireFox) and Web Inspector (for WebKit-based browsers), except it's designed to work remotely, and in particular, to allow you debug web pages on a mobile device such as a phone.