I'm fairly new to Ruby on Rails so sorry if the answer is obvious, I couldn't find anything via search. Right now I have my view rendering _box.js.erb which simply draws a box. Inside _box.js.erb, which works correctly under normal circumstances, I introduce a simple syntax error like an unmatched parenthesis. When I load the webpage, my box doesn't show up. I look in logs/development.logs and it has no mention of my javascript syntax error. Is this error being caught somewhere? If so, how can I display it?
The error occurs on the client, not the server, so ROR cannot log it.
If you're using Firefox, install Firebug. Other browsers have JavaScript consoles, usually opened by pressing F-12 or looking on the "developer" options on the application menus.
You could also create a controller to accept javascript errors, so when there's a client side error you can just send it to a javascript error collection endpoint which in turn could take the contents of the error and add it to the Rails log or whatever log.
This old gem does that. I realize this questions is 8 years old.
Related
I have done a microsoft tutorial called Web API with Javascript
I now have a UI made with Javascript and HTML which looks like this:
How do I use the UI? I keep getting a Reference Error. Is there a specific syntax I am supposed to follow when I add and edit something via APIs?
In the future, please copy and paste error messages into your question. I would normally copy and paste the error message in my answer, but I don't want to type it all out :)
The errors (red) mean that you're trying to use JavaScript that is not defined yet. The warnings (yellow) are the reason why.
The second warning says that it could not load the JavaScript. That explains the errors. The first warning might be the reason why. It's saying that the MIME type is empty, when it should be application/javascript.
But you said in the comments that the site.js file is empty when you try to access it directly. Did you save all the JavaScript in step 4 of that tutorial to site.js?
And what are you using as a web server? IIS Express?
I am moving an application from JBoss 7.1.q to WildFly. Parts of the navigation are done with by creating a form in JavaScript and submitting it via the submit method. All of these calls still work with the exception of one.
Instead of navigating to the page, I get a message of
A Generic Exception Occurred while accessing this page.
I grepped through the code to see if someone had created a window.onerror function to catch exceptions but could not find one. Even more odd, I added one to the js page and it failed to catch the exception.
I have waded through the JavaScript with Firebug and Chrome dev tools and from what I can see, everything looks to be OK, but clearly it is not.
I know it is not much to go on. I am looking for ideas for the next steps to triage this issue. I also find it curious that this problem did not appear until the move to WildFly but I have no clue how that could cause this issue - maybe the form posting is more strict?
Any ideas?
I'd like to write a test case (using Selenium, but not the point of this question) to validate that my web application has no script errors\warnings or unhanded exceptions at certain points in time (like after initializing a major library).
This information can easily be seen in the debug consoles of most browsers. Is it possible to execute a javascript statement to get this information programatically?
It's okay if it's different for each browser, I can deal with that.
not so far read about your issue (as far as I understood your problem) here
The idea be the following:
I found, however, that I was often getting JavaScript errors when the page first loaded (because I was working on the JS and was introducing errors), so I was looking for a quick way to add an assert to my test to check whether any JS errors occurred. After some Googling I came to the conclusion that there is nothing built into Selenium to support this, but there are a number of hacks that can be used to accomplish it. I'm going to describe one of them here. Let me state again, for the record, that this is pretty hacky. I'd love to hear from others who may have better solutions.
I simply add a script to my page that will catch any JS errors by intercepting the window.onerror event:
<script type="text/javascript">
window.onerror=function(msg){
$("body").attr("JSError",msg);
}
</script>
This will cause an attribute called JSError with a value corresponding to the JavaScript error message to be added to the body tag of my document if a JavaScript error occurs. Note that I'm using jQuery to do this, so this specific example won't work if jQuery fails to load. Then, in my Selenium test, I just use the command assertElementNotPresent with a target of //body[#JSError]. Now, if any JavaScript errors occur on the page my test will fail and I'll know I have to address them first. If, for some strange reason, I want to check for a particular JavaScript error, I could use the assertElementPresent command with a target of //body[#JSError='the error message'].
Hope this fresh idea helps you :)
try {
//code
} catch(exception) {
//send ajax request: exception.message, exception.stack, etc.
}
More info - MDN Documentation
I don't know if this has been asked before, but what i'd like to be able to do is get data from the error console within the browser itself(if it supports it) this would be for when a user sends off a bug report it'd pull up any errors related to pages at my website for things such as typos in code and other things that somehow managed to slip by. Also, in that regard is there a way to pass the errors from the console to a useable format? If this isn't possible, then i could just tell them to copy and paste what came up from the site itself.
I thought of this right now as i was thinking about how to make the bug reporting system run better since the entire thing is basically ran within the browser and for the backend I can easily just look at error logs but for the frontend ie javascript bits of things it's not goign to be as easy.
So to finish wrap all of this up in one little statement, is there an easy way to get the data from the error console and be able to send it along via javascript ie to a form, or something similar.
You can use the onerror event in JS to get the details of the error. Hoptoad do this for example and log the errors to their console, Their code re-uses lots of nice JS scripts including a printStackTrace function that is great.....
You can see how they do it here:
http://hoptoadapp.com/javascripts/notifier.js
I get the following error in firebug in Firefox 3 with both MooTools and jQuery:
"p.onStatusChange is not a function".
I've noticed this error frequently in firebug since one of the latest updates of FF3. However, it has started appearing with code that hasn't been changed in some time and that was not reporting errors previously. The errors happens when ajax results are returned. It shows up in different applications that use separate javascript libraries, MooTools and jQuery.
Does anyone have any idea why these errors are appearing? My intuition tells me that it is something in Firefox that changed, but I can't find any information online currently. The ajax calls still work fine, but I am wary of just going with my intuition and leaving script errors in my code.
Thanks,
Jason
I get it in tabBrowser instead:
chrome://browser/content/tabbrowser.xml
(4) errors occur:
p.onStatusChange
p.onProgressChange
p.onStateChange
p.onSecurityChange
What I found was that the add-on "PDF Download" was causing these errors. The best way for me to check was to go to a page that produced the errors, turn off all the add-ons, and turn them on one-by-one (starting with Firebug). Instead of going one-by-one, I actually turned them on in lots of 3 to help identify the problem sooner.
Here is the reference for the function NsIDownloadProgressListener. It looks like it has been deprecated.