Javascript Methodname is replaced with !== - javascript

On the server lies a html file with javascript code included.
This javascript code includes a method called something like "CheckObject".
This file works for all users, except one specific (but important).
He gets a javascript error and in his browser sourcode appears something unbelievable:
The methodname "CheckObject" is replaced with "Check!==ect", means the "Obj" of the method name is replaced with !==.
Why could that be?
Hope anybody can help me!
Best regards

If he's using a browser that supports extensions (like Firefox, Chrome, and some others), it's probably worth disabling all of the extensions and seeing if the problem goes away.
If you haven't already, I'd completely clear his cache in case there was a bad page transfer once and the browser is reusing it.
I can't imagine how it would be happening reliably otherwise.

Related

Define custom function in Firebug

I am a chronic user of Firebug, and I frequently need to log various stuff so that I can see what I am doing. The console.log function is a lot to type. Even if I assign it to a single letter variable like q = console.log, I have to do it every time I fire up Firebug. Is there any way to do it such that q always refer to console.log (unless, of course, I override it in my session)?
To answer your question, the functionality doesn't currently exist, however I have found the firebug developers to be very responsive in the past. Why don't you put in a feature request on their forum, or better yet, code it up yourself, and ask them to add it?
Depending on your IDE, simply setup a code snippet (I use Flash Develop, so Tools -> Code Snippets).
I believe this to be a better way than setting up redirect scripts and what not, because it stops the Firebug namespace from being polluted, and makes it easier/more consistent to debug if your debugging breaks down.
The screenshot shows me using Flash Develop, hitting Ctrl+B, then hit enter. The pipe (|) in the snippet indicates where the cursor will be placed to start typing after inserting the snippet.

Programatically retrieve count of javascript errors on page

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

Strange Javascript/vbscript behavior when opening file from browser

An old web application I recently have to work with is having an issue. There is an input element that contains the following:
onClick="javascript:Run('**SomeFilePath.mdb**');"
What this is supposed to do is open a users respective .mdb file.
First off, there is no javascript Run function defined anywhere. I searched online because I thought maybe it's an old javascript built-in, but I couldn't find anything.
Second off, there IS a vbscript Run() function, that implements the described behavior, defined in the source code, but as far as I know javascript can't call that other than via ajax, which as you can see isn't what is happening.
The strange part is this works for some users!
If anyone could shed some light as to why I'd appreciate it!
EDIT: The only browser I'm dealing with is IE. I know there is an active-x way to open a file, which is what the vbscript Run() function I mentioned above is using.
Update: So after more investigation/research, it would seem like when IE doesn't find the javascript Run() function it defaults to the vbscript Run() function that IS defined. However this only occurs on some versions of IE. Can anyone confirm this behavior?
Research links:
Comment referring to how IE defaults w/ scripting
Msdn article about using both script types in same page
Yes, you can run vbscript from javascript and vice-versa, i do it sometimes when one language doesn't support something the other does.
You can indicate in your script which is the default language in case you don't specify it like .
You can also specify it while calling the function like vbscript:functionname("..") or javascript:functionname("..")
As you noticed there are cases where the browser gets confused and doesn't find the function because he searches/executes the function in the wrong language.
This behavior is influenced i suppose by version also but surely by in which order the logic flows in your script, if the browser first executes a javascript he tends to go further in this language in case of doubt.
So to evade this
don't mix the two unless realy necessary, translate your vbscript function in javascript)
try to always use javascript, vbscript is less good at handling DOM etc
in case they are mixed, specify the correct scriptlanguage when you call a function
when opening a script tag, also give the correct language like or
So, specific, to solve your problem translate the vbsripts function to javascript and if not possible, call your function like onClick="vbscript:Run('**SomeFilePath.mdb**')"

Prevent Javascript from Stopping when Error is Encountered

Our product inserts a script into client's websites, kind of like a live chat box.
Often, clients' websites have buggy javascript that also stops our code (the browser stops execution when errors are encountered). Is there any way to make our code still execute even though there are errors in the console about things like undefined methods or variables?
Thanks for your help.
The short answer is that you really can't.
"Solution" #1: You could insist that YOUR 3rd party code run before anyone else's. In most cases, this isn't possible or even desirable.
"Solution" #2: You could insist that the 1st party engineers wrap all 3rd party code in try/catch blocks. But, this solution really doesn't buy you any guarantee, because very frequently 3rd party libraries attach additional <script> tags to the page - these would not fall under the "jurisdiction" of the try/catch scope enclosing the code which created this/these tag(s).
"Solution" #3: You could build YOUR app entirely within the scope of an <iframe>, thereby avoiding the issue entirely. Unfortunately, even if you're very smart, you'll quickly run into cross domain violations, 3rd party cookie restrictions, and the like. It's very probable that this will not work for you.
"Solution" #4: You could explain the issue to your client, and have them demand that the other 3rd party code run cleanly. I say this is a "solution" because, frankly, it's not a "solution" to your question if your question is how to avoid doing exactly this.
Unfortunately, option #4 is your best bet. It may help if you observe other 3rd party libraries "breaking" in the same fashion: you can tell your client "hey, it's not just me - X, Y, and Z are all also 'broken' because of <name of other 3rd party library>." It may cause them to put the heat on the offending code, which makes the web a happier place for all involved.
As others have said, continuing after an error might not be the best thing to do but you can try this:
function ignoreerror()
{
return true
}
window.onerror=ignoreerror();
More details here
The onerror event fires whenever an JavaScript error occurs (depending
on your browser configuration, you may see an error dialog pop up).
The onerror event is attached to the window object, a rather unusual
place to take refuge in, but for good reason. It is attached this way
so it can monitor all JavaScript errors on a page, even those in the
section of the page.
Opera has a page with more details
Browsers supporting window.onerror
Chrome 13+
Firefox 6.0+
Internet Explorer 5.5+
Opera 11.60+
Safari 5.1+
You can't from your code - they need to use try/catch for questionable pieces of script.
You could have them insert an iframe into their page instead of you trying to inject code using a script tag like so: http://jsfiddle.net/EzMGD/ Notice how the script throws an error yet we can still see the content in the iframe. The iframe should help from using each others variables if applicable.
<script>
MeaningOfLife();
</script>
<iframe src="http://bing.com"></iframe>​
Or inject the code so it's the very first or very last script.
Well, to me that work fine:
element = document.querySelector('.that-pretty-element');
if (element != null) {
element.onclick = function () {
alert(" I'm working beibi ;) ");
}
}
querySelector() returns false, so, we can verify with if's

How to help the debugger see my javascript, or how to best refactor my script to help make it debugger-friendly?

I have an ASP.NET MVC project that uses some simple AJAX functionality through jQuery's $.get method like so:
$.get(myUrl, null, function(result) {
$('#myselector').html(result);
});
The amount of content is relatively low here -- usually a single div with a short blurb of text. Sometimes, however, I am also injecting some javascript into the page. At some point when I dynamically include script into content that was itself dynamically added to the page, the script still runs, but it ceases to be available to the debugger. In VS2008, any breakpoints are ignored, and when I use the "debugger" statement, I get a messagebox saying that "no source code is available at this location." This fails both for the VS2008 debugger and the Firebug debugger in Firefox. I have tried both including the script inline in my dynamic content and also referencing a separate js file from this dynamic content -- both ways seemed to result in script that's unavailable to the debugger.
So, my question is twofold:
Is there any way to help the debugger recognize the existence of this script?
If not, what's the best way to include scripts that are used infrequently and in dynamically generated content in a way that is accessible to the debuggers?
I can not comment yet, but I can maybe help answer. As qwerty said, firefox console can be the way to go. I'd recommend going full bar and getting firebug. It hasn't ever missed code in my 3 years using it.
You could also change the way the injected javascript is added and see if that effects the debugger you're using. (I take it you're using Microsoft's IDE?).
In any case, I find the best way to inject javascript for IE is to put it as an appendChild in the head. In the case that isn't viable, the eval function (I hate using it as much as you do) can be used. Here is my AJAX IE fixer code I use. I use it for safari too since it has similar behavior. If you need that too just change the browser condition check (document.all for IE, Safari is navigator.userAgent.toLowerCase() == 'safari';).
function execajaxscripts(obj){
if(document.all){
var scripts = obj.getElementsByTagName('script');
for(var i=0; i<scripts.length; i++){
eval(scripts[i].innerHTML);
}
}
}
I've never used jquery, I preferred prototype then dojo but... I take it that it would look something like this:
$.get(myUrl, null, function(result) {
$('#myselector').html(result);
execajaxscripts(result);
});
The one problem is, eval debug errors may not be caught since it creates another instance of the interpreter. But it is worth trying.. and otherwise. Use a different debugger :D
This might be a long shot, but I don't have access to IE right now to test.
Try naming the anonymous function, e.g.:
$.get(myUrl, null, function anon_temp1(result) {
$('#myselector').html(result);
});
I'm surprised firebug is not catching the 'debugger' statement. I've never had any problems no matter how complicated the JS including method was
If this is javascript embedded within dynmically generated HTML, I can see where that might be a problem since the debugger would not see it in the initial load. I am surprised that you could put it into a seperate .js file and the debugger still failed to see the function.
It seems you could define a function in a seperate static file, nominally "get_and_show" (or whatever, possibly nested in a namespace of sorts) with a parameter of myUrl, and then call the function from the HTML. Why won't that trip the breakpoint (did you try something like this -- the question is unclear as to whether the reference to the .js in the dynamic HTML was just a func call, or the actual script/load reference as well)? Be sure to first load the external script file from a "hard coded" reference in the HTML file? (view source on roboprogs.com/index.html -- loads .js files, then runs a text insertion func)
We use firebug for debug javascript, profile requests, throw logs, etc.
You can download from http://getfirebug.com/
If firebug don't show your javascript source, post some url to test your example case.
I hope I've been of any help!
If you add // # sourceURL=foo.js to the end of the script that you're injecting then it should show up in the list of scripts in firebug and webkit inspector.
jQuery could be patched to do this automatically, but the ticket was rejected.
Here's a related question: Is possible to debug dynamic loading JavaScript by some debugger like WebKit, FireBug or IE8 Developer Tool?

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