Is there a way to debug or trace every JavaScript event in Internet Explorer 7?
I have a bug that prevents scrolling after text-selecting, and I have no idea which event or action creates the bug. I really want to see which events are being triggered when I move the mouse for example.
It's too much work to rewire the source and I kind of hoped there was something like a sniffer which shows me all the events that are triggered.
Loop through all elements on the page which have an onXYZ function defined and then add the trace to them:
var allElements = document.all; // Is this right? Anyway, you get the idea.
for (var i in allElements) {
if (typeof allElements[i].onblur == "function") {
var oldFunc = allElements[i].onblur;
allElements[i].onblur = function() {
alert("onblur called");
oldFunc();
};
}
}
You might want to try Visual Studio 2008 and its feature to debug JavaScript code.
If the problem is not specific to Internet Explorer 7 but also occurs in Firefox, then another good way to debug JavaScript code is Firefox and the Firebug add-on which has a JavaScript debugger. Then you can also put console.log statements in the JavaScript code which you can then see the output of in the Console Window in Firebug, instead of using alerts which sometimes mess up the event chain.
#[nickf] - I'm pretty sure document.all is an Internet Explorer specific extension.
You need to attach an event handler, there's no way to just 'watch' the events. A framework like jQuery of the Microsoft Ajax library will easily give you methods to add the event handlers. jQuery is nice because of its selector framework.
Then I use Firebug (Firefox extension) and put in a breakpoint. I find Firebug is a lot easier to set up and tear down than Visual Studio 2008.
Borkdude said:
You might want to try Visual Studio 2008 and its feature to debug JavaScript code.
I've been hacking around event handling multiple times, and in my opinion, although classical stepping debuggers are useful to track long code runs, they're not good in tracking events. Imagine listening to mouse move events and breaking into another application on each event... So in this case, I'd strongly advise logging.
If the problem is not specific to Internet Explorer 7 but also occurs in Firefox, then another good way to debug JavaScript code is Firefox and the Firebug add-on which has a JavaScript debugger.
And there's also Firebug Lite for Internet Explorer. I didn't have a chance to use it, but it exists. :-) The downside of it is that it doesn't a fully-fledged debugger, but it has a window.console object, which is exactly what you need.
It's basic, but you could stick alerts or document.write calls in when you trigger something.
The obvious way would be to set up some alerts for various events something like:
element.onclick = function () { alert('Click event'); }
Otherwise you have a less intrusive option of inserting your alerts into the dom somewhere.
But, seriously consider using a library like jQuery to implement your functionality. Lots of the cross-browser issues are solved problems and you don't need to solve them again. I am not sure exactly of the functionality you are trying to achieve but there are most probably plenty of scrolling and selecting plugins for jQuery you could use.
I am not sure on the exact code (it has been a while since I wrote complex JavaScript code), but you could enumerate through all of the controls on the form and attach an event that outputs something when the event is triggered.
You could even use anonymous functions to wrap the necessary information for identifying which event was triggering.
One thing I like to do is create a bind function in JavaScript (like what you can find in the Prototype library) specifically for events, so that it passes the "event" object along to the bound function. Now, if you were to do this, you could simply throw in a trace call that will be invoked for every handler that uses it. And then remove it when it's not needed. One place. Easy.
However, regardless of how you get the trace statement to be called, you still want to see it. The best strategy is to have a separate pane or window handing the trace calls. Dojo Toolkit has a built-in console that runs in Internet Explorer, and there are other similar things out there. The classic way of doing it is to create a new window and document.write to it.
I recommend attaching a date-time to each trace. Helped me considerably in the past.
Debugging and alerts usually won't help you, because it interrupts the normal event flow.
Matt Berseth has something that may be the kind of thing you're looking for in Debugging ASP.NET AJAX Applications with the Trace Console AjaxControlToolkit Control.
It's based on the Yahoo YUI logger, YUI 2: Logger.
My suggestion is, use FireFox together with FireBug and use the built-in Debug/Trace objects. They are a charm.
Related
Sometimes the .click capybara function doesn't fire and it doesn't fail either because it assumes that it fired. So I looked around and found that .trigger("click") is more reliable with some drawbacks too.
But I read the github for the trigger() function and it says it doesn't work in selenium.
Is there an alternative function for a reliable click with capybara/ruby in selenium?
ex:
find(el).click
vs
find(el).trigger("click")
No, there is no alternative click function in Capybara with selenium (other than potentially executing JS via execute_script). It's not likely the click isn't firing, it's more likely that it is firing at the "wrong" location due to animation on the page causing the calculated location of the click to be out of date by the time the click actually occurs. In that case disabling animation during testing can often help. If it isn't a wrong location issue, and you can create an example that exhibits the behavior, report it to either geckodriver or chromedriver and they will usually fix it pretty quickly (as long as you provide an example that replicates it).
Sometimes, the element you are trying to click is hidden or overlapped, in those cases you have to use-
find(el).trigger("click", visible: false)
Hope that helps.
One benefit of calling functions directly from markup is that it is easier to track what's being called. I would like to know if there is an browser addon or something that supports a "Goto javascript source function" for each of the events attached (bound) to an element. Ideally this would take me to the original location it got bound.
You can use FireQuery add on with Firefox browser. It will show you all the events attached to a dom element.
https://addons.mozilla.org/en-US/firefox/addon/firequery/
The built-in Chrome 12 debugger will show you any Event Listeners for any object in the DOM. It can be quite useful, especially to find your way around a larger project. It shows you what event and where the code is.
ok so i am stumped if you go to my site and click the right center "Take a Quick Tour >>>" ..i get this lightbox that appears and i want to close it programmatically and in firebug i can see the x is id "rokbox-close" but running this in firebug
document.getElementById('rokbox-close').click();
but i get this error
TypeError: document.getElementById("rokbox-close").click is not a function
any ideas how to do this
i can run this
document.getElementById("rokbox-close")
and get the element but the click function fails...i dont have jquery installed so i was wondering if there is a javascript thing i am missing
Not all browsers have a "click()" function associated with buttons and anchors and etc. IE does (I think), but (for example) Firefox doesn't.
edit — wow according to MDC, Firefox 5 will support this.
If you were using a framework such as jQuery, then that code might allow you to do what you want. (With jQuery you definitely can.)
(Also, strictly speaking, we're not talking about an event here. We're talking about the ability to trigger the event handling mechanism programatically.)
If you use simple JavaScript istead of 'click' use 'onclick':
document.getElementById("rokbox-close").onclick = youClickHandlerFunction
If you use jQuery use:
$('#rokbox-close').click(youClickHandlerFunction)
See more info here: http://www.quirksmode.org/js/introevents.html
Or here: http://api.jquery.com/click/
The click() function is something that is not supported by all browsers. You're probably thinking of the click handler that jQuery provides.
For a more complete view of why click() isn't universally handled, check out this link, which covers the long and twisty history of event handling across different browsers:
http://www.quirksmode.org/js/introevents.html
we're currently developing an application that makes extensive use of popup windows(*) and have run into an issue on IE (this has been reported before but I couldn't find any solution).
The problem is this: our main window M opens a popup window P and keeps a reference to it. P then registers an event handler on an object in M. When the event fires, IE8 bombs out with the following error message:
JScript object expected
ext-all-debug.js (Line 1735, Char 17)
Code: 0
which is the fire-function in EXTUTIL.Event.prototype. The code works fine in Firefox, Opera and Chrome.
I've provided a minimal example that produces this behaviour.
Any help is appreciated.
(*) Yes, there's a good reason for that. And no, Ext.Window is not an option.
Well, at least I got the tumbleweed badge. :-)
As it turns out, you can not use ExtJS to fire events across browser windows in IE. Condor from the ExtJS Community Support Team said:
Ext is NOT safe to be used across windows. Each window should have it's own Ext instance and communication between the two windows should only be done using primitive datatypes (String, Number, Boolean, Date).
This means that you can't register an event handler in a different window, because that would mean passing objects to the other window.
As it turns out, this is not entirely accurate (at least in IE7 and above). You can reference objects across browser windows. What you can't do is use the Ext event system.
The workaround I used is, instead of registering event handlers in P, to have M call methods in P that then fire the events "locally". It is, of course, not quite es elegant or flexible, but it does work nicely in all browsers. Besides, I think it is good practice to keep cross-window-communication simple and well defined. If you use event handlers you have to carefully keep track of what happens where, for instance you need to make sure you unregister all event handlers before the window is closed.
with firebug i only knows how to see what ajax-files are called.
i have a jquery mouse click event handler bounded to a link element.
is it possible to see what javascript code is used when clicking on an element in case you forgot if you got an event handler or other javascript code coupled to it?
You can use the profiler in Firebug. Go to the Console tab, and click Profile above the message area, next to Clear. It will say that the profiler is running. Click the Profile button again, and you'll see a report on what functions were called and how much time was spent in each one.
If you're using a library like jQuery, the output may be little less clear since it will show much of the time was spent in functions from the library (i.e. F(), init(), dimension(), etc). It will show which file each function was defined in though, so you can disregard the ones that are in the library (unless that's what you're looking for).
If you're using anonymous functions, you can give them names so they show up in the profiler - see this article for a thorough (possibly too thorough) explanation.
Use breakpoints ..
reference: http://getfirebug.com/javascript
You should take a look at Eventbug (it requires Firefox 3.6, some of the docs are old):
Downloads:
http://getfirebug.com/releases/eventbug/1.5/
Some background:
http://www.softwareishard.com/blog/firebug/eventbug-alpha-released/
Just add 'debugger;' at your onclickevent, and happy debug it.
*Important: you gotta open the firebug panel and Reload the page