Javascript not working properly on Firefox on URL - javascript

I'm trying to use this simple code:
javascript:document.getElementsByName("tabla-usuarios_length")[0].options[3].text="10000";
I tested it on Chrome(URL) and it works perfectly, also in both Firefox and Google Chrome's Console.
In both console's it works and it gives me like a message "10000" in the console.
In Firefox URL, it redirects like to a blank page with that same message instead of just working on the page I am. so since it goes to that blank page I can't see the results and to come back to the page I was I have to tap on back and of course it reloads losing the possible change that I made with the JS code..
I really need it working with the url stuff since I need to use it with iMacros (URL GOTO=javascript:....) so I can't use it with Console.
Thanks I hope I explained myself correctly.

Three alternatives
wrap a simple command in void()
javascript:void(document.getElementsByName("tabla-usuarios_length")[0].options[3].text="10000");
or - use IIFE
javascript:(function() {document.getElementsByName("tabla-usuarios_length")[0].options[3].text="10000";})();
or, again only with simple command, use , operator like so:
javascript:document.getElementsByName("tabla-usuarios_length")[0].options[3].text="10000",undefined;
Seems Firefox looks at the return value of bookmarklets. If it is udefined it works as expected
All complex bookmarklets I've ever seen were always wrapped in IIFE - which is why they've always worked
Even the wikipedia page (which I only now read) shows this requirement - with one other format for them
javascript:{arbitrary script};void(0);

Related

window.location failing on Android Browser

I've run into this and while the internet seems to be full of answers and discussions on this issue nothing seems to be working.
I'm building a mobile web page where I run a jQuery JavaScript function off a submit button, it calls an AJAX query comes back does it's business and then I get to the dreaded:
window.location = "url";
Now I've personally tried every version of this I've seen deprecated or not:
window.location.href =
window.location.replace() --I know this is achieving something different
window.location.assign()
window.navigate()
document.location =
document.location.href =
document.location.replace()
document.location.assign()
In each instance my Android Browser version 5.5 just stops at the point it is supposed to move through to the next url. I'm using full urls from the "http://..." so not missing that.
In contrast Android Chrome is moving through like a champ. Same Phone. Have I missed some crucially important piece to the puzzle here to get this moving on Android Browser?
My searches online seem to only say that:
window.location.href = '';
...is the most technically correct, right now I'd settle for working rather than technically correct.
If anyone has any ideas or at least some avenues to go off and explore I'll get all over that first thing in the morning.
Thanks for any help you can offer.
I found that this was a result of a faulty AJAX call. The weird thing that was throwing me off was that some items would work within the call (even though the call failed) and some would not.
The answer in my own case was to fix the PHP that the AJAX was calling and then changing pages worked as I would expect it to.

What are the rights ways of debugging javascript?

I made a function called test() in javascript file.Placed a simple alert into it.
In html file, called the method on click of a button. But,it was not being invoked.
Problem was in the 11th function, nowhere related to mine !!!! But, how can a person making his first javascript function suppose to find that out ???
I am looking for best ways to debug javascript.
You can debug javascript using many modern browsers. See this question for details on how to debug in Google Chrome:
How do you launch the JavaScript debugger in Google Chrome?
Furthermore, you shouldn't use alert() for debugging as this can give different results to a production version due to alert() causing a pause in the script.
It is best practice to use console.log() and view the output in the browsers Console.
You can also put debugger in your javascript code to force a breakpoint. However I prefer not to use this as forgetting to remove this before deployment will cause your script to pause, which can be quite embarrassing!
You should use the debug console provided by the browser.
Chrome has it inbuilt, press CTRL + SHIFT + j. In Firefox, install Firebug plugin.
In your code, add alert() to show flow and get values of variables.
Also, use console.log() which will only output to the debug console.
Depending on your browser choice there are debugging options - I tend to use Firefox, so Firebug in my case. There is a question that list options for other browsers - What is console.log and how do I use it?
Unless the project you're working on has already adopted a mechanism for debugging, console.log() tends to be a simple and useful option when tracking down a problem.
Whilst debugging you could take the approach to log out a line when entering a function, like so:
var myFunc = function(el) {
console.log('Inside myFunc');
// Existing code
};
This will enable you to see which functions have been called and give you a rough idea of the order of execution.
You can also use console.log() to show the contents of variables - console.log(el);
Be mindful to remove/disable console.log() calls once you're done as it will likely cause some issues in production.
To answer your question within question,
how can a person making his first javascript function suppose to find that out ???
Well, when something is wrong in JavaScript, for example, you made a syntax error - the script will stop working from there. However, this won't stop HTML from rendering on, so it might look as if everything is correct (especially if your JS is not changing the look of the page) but all the functionality of JS will be dead.
That's why we use the debug tools (listed in the other answers here) to see what's wrong, and in cases like this, it's very easy to notice which function has errors and is causing the whole script to break. This would probably have save a few minutes to your seniors as well.
The best approach would be to test frequently so that whenever you run into errors, you can fix them right away.

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.

Ajax problem using MooTools/jQuery - p.onStatusChange is not a function

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.

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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