i have the problem that some parts of my windchill app run into infinite loops. the following seems to appear sometimes:
i'm using the wizard and created two steps to add something to a table. the wizard is opened in a popup window and immediately loads the first step.
i already found out that the step defined in the html (div with id "wiz_step_contents") gets loaded into an adjacent tag (div with id "wizard_viewport"). i believe this is caused by extjs.
the first step includes script-tags, so when the step is loaded, some scriptfiles are loaded too.
however, when using fiddler to track the network log, sometimes (and only in IE), those included scriptfiles are loaded infinite times until i close the browser window.
and now to my question: how does windchill load new steps? is there a way a step could be loaded again, say, if some flagvariables aren't set that should be set?
edit: it seems that this is caused by the java fileupload applet... any ideas?
JAT, have you tried disabling the Java file upload applet in favor of the Basic Browser functionality? You can set that as a - personal - Preference. QuickLinks>My Settings>Preferences. You would be looking for "File Upload Mechanism".
Related
Context:
I am creating a Chrome extension that hides certain elements of certain sites
In this specific case, I'm trying to hide the main feed of YouTube's home and trending pages
The script has no trouble on all other sites, including Twitter, Facebook etc.
But on YouTube, it's causing the page to crash
Roughly speaking, what the script does is:
Observes any mutation on document (childList: true, subtree: true, characterData: false)
Searches for the existence of certain nodes in the document
Changes some of their styles to hide them (or if already hidden, does nothing)
Adds a small menu into the node with a button to unhide the node
The MutationObserver is never disconnected because it needs to keep watching in the case of single-page apps where the page stays the same but different nodes come and go
So it keeps checking that the hidden nodes are still hidden every time there's any new mutation to the document or its subtree (heavy load on performance, I know - but it works fine on every other site)
YouTube issue:
YouTube always throws up a warning as follows, even when I am not running my script on it (in other words, YouTube's code is already a bit suspect):
[Violation] Added non-passive event listener to a scroll-blocking <some> event. Consider marking event handler as 'passive' to make the page more responsive. See <URL>
The specific event is either touchstart or wheel. This error can display in the 100s of times even when I am not running my script.
When I run my script, this error seems to blow up even more, and display more times than usual
Eventually, the entire page crashes or takes far longer to load than it should (but it does sometimes eventually make it all the way, showing that my extension is not completely breaking down)
There's also another warning that tends to show, [Violation] 'readystatechange' handler took <N>ms
This warning shows far fewer times than the other (see screenshot below)
Interestingly, usually loading youtube.com home page when starting off in a new tab is fine, and my extension successfully hides (i.e. changes styles on + injects some extra HTML into) the node it's meant to hide
I then get a crash or extremely slow page load when I try to navigate within YouTube, e.g. specifically going to the Trending page using the left-hand side menu, OR occasionally when I hit refresh on the page
Things I've tried:
Overriding the default addEventListener method on EventTarget.prototype, which I have so far failed to do successfully - not sure I understand how to do this despite trying a few methods from SO
Blocking the script that this error originates from (desktop_polymer_inlined_html_polymer_flags_v2.js) using the Chrome WebRequest API, but that doesn't work because it breaks the whole page
Questions:
Is it likely that this 'non-passive event listener' warning is interplaying with my script to cause the crashing of the page? Or that my script is causing more listeners to be added than the page would usually?
How can I stop this error from happening (e.g. how do I prevent the event listeners from being created by YouTube's JS)?
Does anyone know anything about the way YouTube is built that would make it crash if you try to 1) modify a style on an element directly 2) add another element into a parent element 3) continually check styles on an element? Builtwith.com was not much help.
Is there something else I am missing here? Another way I can change my content script to make it interplay better with YouTube?*
*I know a tempting answer will be 'don't observe the document'/'observe it less' but this is more or less non-negotiable in terms of the way the browser extension needs to work.
Screenshot:
Chrome profiling:
Note: having looked into them individually, none of the functions that are taking up the huge amount of time are part of my extension. So perhaps YouTube is reacting badly to the DOM modifications that my extension performs.
I am new on add-on development using the SDK.
I want to ask you guys if it is possible to start my extension automatically after I open my browser? At the moment I starts after I press my widget icon in the toolbar (the panel shows a table with some data I get from the DOM).
Another thing I want to ask you: is it possible to show a loading screen (like a ajax gif) inside my panel (my extension needs a few seconds after switching a tab, to get the DOM data) every time I press the toolbar button.
First of all: One question per post, please.
Extensions are always started with the browser. When it comes to SDK add-ons, your main.js will be called. It's your job to perform any additional initialization form there.
Panels contain regular HTML pages and therefore can use images.
It's impossible to tell you more, without you providing more details and the code you got so far!
Is there a way to force reloading only specific resource-files from DevTools?
I'm developing site with ExtJS MVC, that results to almost 100 JS files. Mostly I'm debugging the controller by filling an form -> sending form -> detecting an bug in controller -> fixing it -> reloading whole site -> filling the form again -> another bug -> reload...
It would be very helpful to reload only the controller-part of the code, so that the JS-files contructing the forms would not be affected, thus increasing load times and dropping need to fill the form on every iteration.
So, is it possible? Or could the browser even work this way?
u can use Local Modifications in Source panel (right click in panel) to change or debug Your code, or You can open specific js file in new windwow and than reload it, but I don`t think You can apply reloaded file to site without reloading it itself.
Im playing around with making my first chrome extension. Im making a small extension that monitors the webrequests a page makes. This means that im listening to the: chrome.webRequest.onBeforeRequest.addListener event
I am a little confused on how to execute this code on every page i load. It works on any page if i open the extension web page and run the code in this context. However i would like it to run regardless of having the page open. How do i go around doing this?
I looked at content_scripts, but havent figured out if they are the proper path to take - and ven if they are how do i send a message from my content script to my web page notifying it to run the code. As far as i understand this the content script is first run after the page has been loaded and therefore it does not matter if i call my page and add the listeners, because the show is already over - is this correct?
The wa i understand this is that i cannot add listeners in the content script - hence the need to make this messaging thing - is this correct?
Thank you.
You would put the onBeforeRequest listener in a background page, specifically the persistent variant of it. When the event is invoked, whatever you have in the handler will be run.
I am researching the possibility that I might be able to use a Chrome extension to automate browsing and navigation (conditionally). My hope is that the extension can load a remote page (in the background) and inject a javascript to evaluate clickable links and click (by calling the click method) the appropriate (evaluated by some javascript logic) link, then repeat process for the resulting page.
My ability to javascript is not the problem - but I am struggling to discern whether (or not) a chrome extension can load pages in the back and inject script into them (making the DOM accessible).
I would be pleased if anyone could confirm (or deny) the ability to do so - and if so, some helpful pointers on where I should research next.
#Rob W - it seems the experimental features fit the bill perfectly. But my first tests seem to show the features are still very experimental ... ie. no objects get returned from callbacks:
background.html
function getAllosTabs(osTabs){
var x = osTabs;
alert(x.length); // error: osTabs is undefined
}
function createOffScreenTabCallback(offscreenTab){
document.write("offscreen tab created");
chrome.experimental.offscreenTabs.getAll(getAllosTabs);
alert(offscreenTab); // error: offscreenTab is undefined
}
var ostab = chrome.experimental.offscreenTabs.create({"url":"http://www.google.com"}, createOffScreenTabCallback)
alert(ostab); // error: ostab is undefined
Some further digging into the chromium source code on github revealed a limitation creating offscreenTab from background:
Note that you can't create offscreen tabs from background pages, since they
don't have an associated WebContents. The lifetime of offscreen tabs is tied
to their creating tab, so requiring visible tabs as the parent helps prevent
offscreen tab leaking.
So far it seems like it is unlikely that I can create an extension that browses (automatically and conditionally) in the background but I'll still keep trying - perhaps creating it from script in the popup might work. It won't run automatically at computer startup but it will run when the browser is open and the user clicks the browseraction.
Any further suggestions are highly welcome.
Some clarifications:
there's no "background" tabs except extension's background page (with iframes) but pages loaded in iframes can know they are being loaded in frames and can break or break at even the best counter-framebreaker scripts
offscreenTab is still experimental and is very much visible, as its intended use is different from what you need it for
content scripts, and chrome.tabs.update() are the only way handle the automated navigation part; aside being extremely harsh to program, problems and limitations are numerous, including CSP (Content-Security-Policy), their isolated context isolating event data, etc.
Alternatives... not many really. The thing is you're using your user's computer and browser to do your things and regardless of how dirty they are not, chrome's dev team still won't like it and will through many things at you and your extension (like the v2 manifest).
You can use NPAPI to start another instance chrome.exe --load-extension=iMacros.