I am debugging some code on the MS Edge browser, but it reloaded twice and showed a "This page is having a problem loading" message after two tries. The page has been tested on IE11 or lower, Chrome, and Firefox with no issues.
I have been having trouble bringing up the debugger during page execution by placing the debugger statement in various parts of the code. I have placed it in the first line of the script in the body tag, I have placed it in the first line of $(document).ready(); and even in the script tag in the header. I am so surprised when none of the debuggers triggered other than the one in IE11 (both Chrome and Firefox did not trigger either). Edge of course still continued on its reload loop and saying that it has a problem loading.
My question is - am I not doing this right? Is there a list of when a debugger; statement will not trigger? And more importantly, how do I trigger it in Edge before it reloads twice and throw the error page (For reference, pulling up F12 after it throws the error page gives the DOM of the error page, which is not helpful.)
This is an issue with Edge where the console seems to crash along with the browser. I have noticed it numerous times during development and have not been able to find a solution.
Check in every other browser on an empty cache and see if you are getting any errors in console. Older versions of Edge, before the last service pack were very flakey so I would suggest making sure your environment is upto date.
I am facing a really weird problem. I am calling window.print() from a javascript file. This is working fine in Safari, IE, Firefox... and until two hours ago it worked in Chrome, too. (Version 29.0.1547.57)
I did not change anything essential in my javascript file (really - I just removed some comments...), but what now happens is really weird: In Chrome, the print dialogue does not open when window.print() is called. Nothing happens. But then, when I press reload, the print dialogue opens immediately.
The behaviour in the other browser did not change. And while debugging in Chrome I can see that window.print() is called as expected and the script goes on after that. Only the print dialogue is not shown until pressing reload.
Has anybody ever experienced something like that? I also tried to call window.print() in setTimeout(), but this did not change anything. When I debug the content of the page which shall be printed appears to be perfectly loaded.
I am sorry to ask, but I did not find anything while researching. Any help would be appreciated!
Thank you!
Wasiim is right, there is a Chrome bug where window.print() does not work when there is a <video> tag in the DOM. I solved it by calling this function:
function printPage() {
window.print();
//workaround for Chrome bug - https://code.google.com/p/chromium/issues/detail?id=141633
if (window.stop) {
location.reload(); //triggering unload (e.g. reloading the page) makes the print dialog appear
window.stop(); //immediately stop reloading
}
return false;
}
From my experience this is due to continued background traffic, e.g. ajax calls and the like that prevent Chrome from feeling the that page is loaded completely. The reload breaks all traffic and thus the print dialog pops up.
This is a particular gotcha in Visual Studio 2013 where BrowserLink continually ticks away in the background.
This can be tested by disabling BrowserLink via the setting below:
<configuration>
<appSettings>
<add key="vs:EnableBrowserLink" value="false"/>
</appSettings>
</configuration>
I have exactly same problem with Chrome. You need to manually reload page:
Print
If by any chance someone is using VS2013 with chrome, this problem is caused by the BrowserLink funcionality.
see SO answer here
Similar behavior in Safari. It is caused by opened HTTP request(s) on background.
When any HTTP request is in progress, window.print() is executed successfully, but no dialog is opened!
You will have this issue, when you use a long polling (for server push). Because client will have already opened HTTP connection for a long time, window.print() will never work.
I am most certain you are experiencing this issue because you have a video element on your page - most probably an MP4.
If you disable this video / or have an OGV video instead, the printing should work fine.
It is a bug in chrome itself due to limitations of Chrome's video implementation. It is also important to note that if the user prints manually with ctrl-p / cmd-p, print functions correctly
http://code.google.com/p/chromium/issues/detail?id=141633
Hope this helps :)
When stepping through JavaScript code in Google Chrome debugger, how do I terminate script execution if I do not want to continue? The only way I found is closing the browser window.
Pressing "Reload this page" runs the rest of the code and even submits forms as if pressing F8 "Continue".
UPDATE:
When pressing F5 (Refresh) while a script is paused:
Google Chrome (v22) runs the script. If the script submits HTTP request, the HTTP response for that request is displayed. The original page is not refreshed.
IE 9 just freezes. However IE has an option "Stop Debugging" which, when pressed (provided you did not press F5 earlier), continues to run the script outside debugger.
Firebug behaves identically to Chrome.
Closing and then opening again the browser window is not always the next easiest way
because it will kill browser session state and that may be important. All your breakpoints are also lost.
UPDATE (Jan 2014):
Refresh while debugging:
Chrome v31: lets scripts to run and stops on further breakpoints (but does not submit ajax requests), then refreshes.
IE 11: refresh does nothing, but you can press F5 to continue.
Firefox v26: lets scripts to run but does not stop on further breakpoints, submits ajax requests, then refreshes.
Kind of progress!
Navigate to the same page while debugging:
Chrome v31: same as Refresh.
IE 11: scripts are terminated, new browser session is started (same as closing and opening again).
Firefox v26: nothing happens.
Also juacala suggested an effective workaround. For example, if you are using jQuery, running delete $ from console will stop execution once any jQuery method is encountered. I have tested it in all above browsers and can confirm it is working.
UPDATE (Mar 2015):
Finally, after over 2 years and almost 10K views, the right answer was given by Alexander K. Google Chrome has its own Task Manager which can kill a tab process without closing the tab itself, keeping all the breakpoints and other stuff intact.
I even went as far as BrowserStack.com to test it in Chrome v22 and found that this was working this way even at that time.
Juacala's workaround is still useful when debugging in IE or Firefox.
UPDATE (Jan 2019):
Chrome Dev Tools at last added a proper way to stop script execution which is nice (although a bit hidden). Refer to James Gentes's answer for details.
In Chrome, there is "Task Manager", accessible via Shift+ESC or through
Menu → More Tools → Task Manager
You can select your page task and end it by pressing "End Process" button.
As of April 2018, you can stop infinite loops in Chrome:
Open the Sources panel in Developer Tools (Ctrl+Shift+I**).
Click the Pause button to Pause script execution.
Also note the shortcut keys: F8 and Ctrl+\
2020 April update
As of Chrome 80, none of the current answers work. There is no visible "Pause" button - you need to long-click the "Play" button to access the Stop icon:
One way you can do it is pause the script, look at what code follows where you are currently stopped, e.g.:
var something = somethingElse.blah;
In the console, do the following:
delete somethingElse;
Then play the script: it will cause a fatal error when it tries to access somethingElse, and the script will die. Voila, you've terminated the script.
EDIT: Originally, I deleted a variable. That's not good enough. You have to delete a function or an object of which JavaScript attempts to access a property.
[2022 edit: this was reported as https://bugs.chromium.org/p/chromium/issues/detail?id=774852 and https://bugs.chromium.org/p/chromium/issues/detail?id=1112863 in 2017, and was just recently marked as fixed 5 years later, so if you are still experiencing this, you should update Chrome (and in general keep it updated). If you are experiencing this issue in 2023 or forward, it may be a different issue, a bug regression, etc.]
If you are encountering this while using the debugger statement,
debugger;
... then I think the page will continue running forever until the js runtime yields, or the next break. Assuming you're in break-on-error mode (the pause-icon toggle), you can ensure a break happens by instead doing something like:
debugger;throw 1;
or maybe call a non-existent function:
debugger;z();
(Of course this doesn't help if you are trying to step through functions, though perhaps you could dynamically add in a throw 1 or z() or somesuch in the Sources panel, ctrl-S to save, and then ctrl-R to refresh... this may however skip one breakpoint, but may work if you're in a loop.)
If you are doing a loop and expect to trigger the debugger statement again, you could just type throw 1 instead.
throw 1;
Then when you hit ctrl-R, the next throw will be hit, and the page will refresh.
(tested with Chrome v38, circa Apr 2017)
Refering to the answer given by #scottndecker to the following question, chrome now provides a 'disable JavaScript' option under Developer Tools:
Vertical ... in upper right (in Developer Tools menu, not in Chrome main menu)
Settings (in newer Chrome versions it is visible separately as a cogwheel besides the ... button, not under it)
And under 'Preferences' go to the 'Debugger' section at the very bottom and select 'Disable JavaScript'
Good thing is you can stop and rerun again just by checking/unchecking it.
Good question here. I think you cannot terminate the script execution. Although I have never looked for it, I have been using the chrome debugger for quite a long time at work. I usually set breakpoints in my javascript code and then I debug the portion of code I'm interested in. When I finish debugging that code, I usually just run the rest of the program or refresh the browser.
If you want to prevent the rest of the script from being executed (e.g. due to AJAX calls that are going to be made) the only thing you can do is to remove that code in the console on-the-fly, thus preventing those calls from being executed, then you could execute the remaining code without problems.
I hope this helps!
P.S: I tried to find out an option for terminating the execution in some tutorials / guides like the following ones, but couldn't find it. As I said before, probably there is no such option.
http://www.codeproject.com/Articles/273129/Beginner-Guide-to-Page-and-Script-Debugging-with-C
http://www.nsbasic.com/app/tutorials/TT10.htm
You can pause on any XHR pattern which I find very useful during debugging these kind of scenarios.
For example I have given breakpoint on an URL pattern containing "/"
If you have a rogue loop, pause the code in Google Chrome debugger (the small "||" button while in Sources tab).
Switch back to Chrome itself, open "Task Manager" (Shift+ESC), select your tab, click the "End Process" button.
You will get the Aww Snap message and then you can reload (F5).
As others have noted, reloading the page at the point of pausing is the same as restarting the rogue loop and can cause nasty lockups if the debugger also then locks (in some cases leading to restarting chrome or even the PC). The debugger needs a "Stop" button. Nb: The accepted answer is out of date in that some aspects of it are now apparently wrong. If you vote me down, pls explain :).
Go to the Sources tab and select Filesystem subTab
Select a folder, containing the file you execute
Accept folder access recuest
Select the file you execute
Put a breakpoint inside the file you execute
Click the "Pause script execution option"
Select the copy link address option in the RMB context menu
Paste the copied address into the browser address bar to open the file
File execution will be stopped at the breakpoint
Open the source tab in 'Developer Tools', click on a line number in a script that is running, this will create a breakpoint and the debugger will break there.
There are many appropiate solution to this problem as mentioned above in this post, but i have found a small hack that can be inserrted in the script or pasted in the Chromes console (debugger) to achieve it:
jQuery(window).keydown(function(e) { if (e.keyCode == 123) debugger; });
This will cause execution to be paused when you hit F12.
I would like to achieve that when clicking in an image, in the div where this image is, a div with other content from another .html is loaded, but I can't get it done.
If I do, the following, it works perfectly:
$('#windows_link').click(function(){
$('#apps_container').html("Hi!");
});
But if I do the following, it does not work; it doesn't do anything actually:
$('#windows_link').click(function(){
$('#apps_container').load('windows_apps.html #apps_container');
});
Any help, please?
Thanks a lot in advance!
When you're local any other HTML path is treated as another domain in certain browsers (Chrome is on the list). That means any AJAX request (what .load() does underneath) you attempt will be blocked by the same origin policy.
What you have will likely work fine...just not locally, in Chrome.
You can verify this by testing in another browser like Firefox, or by launching chrome with a command line switch to disable this safety feature (only for testing!, turn it off after):
chrome.exe --disable-web-security
If the first try works correctly, i assume the problem is here
.load('windows_apps.html #apps_container');
When you click the link, do you see a call in your .net panel of firebug or of your debugging console(does the ajax call complete succesfully)?
Is windows_apps.html in the same folder of the page script that calls it?
is there a div called apps_container into that page?
I have a situation where I'm inserting javascript generated HTML code into a DIV. One would think this would be a no brainer, but for some reason, once the code is in, the status bar and tab loading graphics start up in both browsers and never stop again. The page continually appears to be loading data, but in reality, there's nothing more to load. Any idea why this may be happening? Solutions? I appreciate any help. Thanks!
Install the Firebug plug-in for Firefox. Open it up and got to the NET tab. That will allow you to see your network activity. Something on the server may be stalling. This will help you find it.