There are a couple of pages that have started to load incorrectly on most browsers on my computer:
https://www.appfrontier.com/documentation/
https://login.live.com/
When these pages load I see blank space and overlapping text, which seems to be the result of JavaScript not running properly on the page.
This happens in Chrome, FireFox, Opera, IE, and Edge. I am using Windows 10.
However, when I load these same pages in Brave browser, they load fine and everything works.
This issue is specific to one computer... On my other computer the pages load fine on all browsers.
I tried to figure out the problem and notice that when chrome requests for some HTML/JavaScript files, an error occurs when evaluating window.navigator.userAgent. For example, the browser should retrieve the following .js file:
function isIE() {
var ua = window.navigator.userAgent;
// do stuff depending on the browser
}
However, instead, the below code is returned as the response to retrieve the .js file:
function isIE() {
var ua = window.'Mozilla/5.0 (PlayStation 4 3.11) AppleWebKit/537.73 (KHTML, like Gecko)'
// do stuff depending on the browser
}
Because of this, an error occurs "Uncaught SyntaxError: Unexpected string"
I think something is wrong with my computer but I have no idea what. I tried uninstalling and reinstalling each browser but that does not work. Any suggestions are appreciated.
Found out the problem. It was Iolo System Mechanic. Looking back I feel stupid for using the product because it said that it was actively "cleaning up" windows and internet junk files. I'm guessing it deleted something that broke JavaScript loading for pages that use window.navigator.userAgent.
I'm trying to display an image selected from the local machine and I need the location of that image for a JavaScript function. But I'm unable to get the location.
To get the image location, I tried using console.log, but nothing returns.
console.log(document.getElementById("uploadPreview"));
Here's the HTML code:
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<div align="center" style="padding-top: 50px">
<img align="center" id="uploadPreview" style="width: 100px; height: 100px;" />
</div>
<div align="center" style="padding-left: 30px">
<input id="uploadImage" type="file" name="myPhoto" onchange="PreviewImage();" />
</div>
<script type="text/javascript">
function PreviewImage() {
var oFReader = new FileReader();
oFReader.readAsDataURL(document.getElementById("uploadImage").files[0]);
oFReader.onload = function (oFREvent) {
document.getElementById("uploadPreview").src = oFREvent.target.result;
console.log(document.getElementById("uploadPreview").src);
};
}
</script>
</body>
</html>
Console Output:
Here's the warning:
DevTools failed to load SourceMap: Could not load content for
chrome-extension://alplpnakfeabeiebipdmaenpmbgknjce/include.preload.js.map:
HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
That's because Chrome added support for source maps.
Go to the developer tools (F12 in the browser), then select the three dots in the upper right corner, and go to Settings.
Then, look for Sources, and disable the options:
"Enable JavaScript source maps"
"Enable CSS source maps"
If you do that, that would get rid of the warnings. It has nothing to do with your code. Check the developer tools in other pages and you will see the same warning.
Go to Developer tools → Settings → Console → tick "Selected context only". The warnings will be hidden. You can see them again by unticking the same box.
The "Selected context only" means only the top, iframe, worker and extension contexts. Which is all that you'll need, the vast majority of the time.
Fixing "SourceMap" error messages in the Development Tools Console caused by Chrome extensions:
Examples caused by McAfee extensions:
DevTools failed to load SourceMap: Could not load content for chrome-extension://klekeajafkkpokaofllcadenjdckhinm/sourceMap/content.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
DevTools failed to load SourceMap: Could not load content for chrome-extension://fheoggkfdfchfphceeifdbepaooicaho/sourceMap/chrome/content.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
DevTools failed to load SourceMap: Could not load content for chrome-extension://fheoggkfdfchfphceeifdbepaooicaho/sourceMap/chrome/iframe_handler.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
If you are developing, then you need "Enable JavaScript source maps" and "Enable CSS source maps" checked to be able see your source code in Chrome Developer Tools. Unchecking those takes away your ability to debug your source code. It is like turning off the fire alarm instead of putting out the fire. You do not want to do that.
Instead you want to find the extensions that are causing the messages and turn them off. Here is how you do that:
Go to the three dots in the upper right hand corner of Chrome.
Go to "More Tools" and click on "Extensions".
Do this for one extension at a time until no more "SourceMap" errors are in the console:
Turn off the extension by sliding the switch to the left.
Reload the page that you were using the Development Tools on.
Check if any of the "SourceMap" error messages disappeared.
If any did, then that extension was causing those messages.
Otherwise, that extension can be turned back on.
After determining which extensions caused the issue either:
If you need it, then contact the maker to have them fix the issue.
Otherwise, remove the extension.
I stumbled upon this Stack Overflow question after discovering loads of source map errors in the console for the Edge browser. (I think I had disabled the warnings in the Chrome browser long ago.)
For me it meant first realising what a source map is; please refer to Macro Mazzon's answer to understand this. Since it's a good idea, it was just a case of finding out how to turn them on.
It's as simple as adding this line in your webpack.config.js file -
module.exports = {
devtool: "source-map",
}
Now that Edge could detect a source map, the errors disappeared.
Apologies if this answer insults anybody's intelligence, but maybe somebody reading this will be as clueless about source maps as I was.
The include.prepload.js file will have a line like below, probably as the last line:
//# sourceMappingURL=include.prepload.js.map
Delete it and the error will go away.
For me, the problem was caused not by the application in development itself, but by the Chrome extension React Developer Tool. I solved it partially by right-clicking the extension icon in the toolbar, clicking "Manage extension" and then enabling "Allow access to files URLs." But this measure fixed just some of the alerts.
I found issues in the React repository that suggests the cause is a bug in their extension and is planned to be corrected soon - see issues 20091 and 20075.
You can confirm is extension-related by accessing your application in an anonymous tab without any extension enabled.
Chrome has changed the UI in 2022, so this is a new version of the most upvoted reply.
Open the dev tools (hit F12 or Option + Command + J)
Select the gear at the top. There are two gears in that area, so be sure to select the one at the top, top.
Locate the Sources section
Deselect "Enable JavaScript source maps"
Check to see if it worked!
Right: it has nothing to do with your code. I've found two valid solutions to this warning (not just disabling it). To better understand what a source map is, I suggest you check out this answer, where it explains how it's something that helps you debug:
The .map files are for JavaScript and CSS (and now TypeScript too) files that have been minified. They are called SourceMaps. When you minify a file, like the angular.js file, it takes thousands of lines of pretty code and turns it into only a few lines of ugly code. Hopefully, when you are shipping your code to production, you are using the minified code instead of the full, unminified version. When your app is in production, and has an error, the sourcemap will help take your ugly file, and will allow you to see the original version of the code. If you didn't have the sourcemap, then any error would seem cryptic at best.
First solution: apparently, Mr Heelis was the closest one: you should add the .map file and there are some tools that help you with this problem (Grunt, Gulp and Google closure for example, quoting the answer). Otherwise you can download the .map file from official sites like Bootstrap, jQuery, font-awesome, preload and so on... (maybe installing things like popper or swiper by the npm command in a random folder and copying just the .map file in your JavaScript/CSS destination folder)
Second solution (the one I used): add the source files using a CDN (content delivery network). (Here are all the advantages of using a CDN). Using content delivery network (CDN) you can simply add the CDN link, instead of the path to your folder. You can find CNDs on official websites (Bootstrap, jquery, popper, etc.) or you can easily search on some websites like Cloudflare, cdnjs, etc.
Extensions without enough permissions on Chrome can cause these warnings, for example for React developer tools. Check if the following procedure solves your problem:
Right click on the extension icon.
Or
Go to extensions.
Click the three-dot in the row of React developer tool.
Then choose "This can read and write site data".
You should see three options in the list. Pick one that is strict enough based on how much you trust the extension and also satisfies the extension's needs.
I appreciate this is part of your extensions, but I see this message in all sorts of places these days, and I hate it: how I fixed it (this fix seems to massively speed up the browser too) was by adding a dead file
physically create the file it wants it/where it wants it, as a blank file (for example, "popper.min.js.map")
put this in the blank file
{
"version": 1,
"mappings": "",
"sources": [],
"names": [],
"file": "popper.min.js"
}
make sure that "file": "*******" in the content of the blank file matches the name of your file ******.map (minus the word ".map")
(I suspect you could physically add this dead file method to the addon yourself.)
I do not think the warnings you have received are related. I had the same warnings which turned out to be the Chrome extension React Dev Tools. I removed the extension and the errors were gone.
You have just missing files.
Go to the website https://www.cdnpkg.com/.
Download what you need and copy it to the right folder.
For me, the warnings were caused by the Selenium IDE Chrome extension. These warnings appeared in the Console on every page load:
DevTools failed to load source map: Could not load content for chrome-extension://mooikfkahbdckldjjndioackbalphokd/assets/atoms.js.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
DevTools failed to load source map: Could not load content for chrome-extension://mooikfkahbdckldjjndioackbalphokd/assets/polyfills.js.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
DevTools failed to load source map: Could not load content for chrome-extension://mooikfkahbdckldjjndioackbalphokd/assets/escape.js.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
DevTools failed to load source map: Could not load content for chrome-extension://mooikfkahbdckldjjndioackbalphokd/assets/playback.js.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
DevTools failed to load source map: Could not load content for chrome-extension://mooikfkahbdckldjjndioackbalphokd/assets/record.js.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
Since Selenium IDE was already set to be able to read site data on all sites, I uninstalled it. (I read in another comment here that you might try enabling more permissions for an extension instead of removing it.) In my case, removing Selenium IDE (Chrome extension) got rid of the warnings.
It is also possible to add the file that is missing, aside with other .js libraries in the same folder (no need to reference the .map in the .html file, <script> tag).
I had the same error, when trying to code in Backbone.js.
The problematic file was backbone-min.js, and the line that created the error was sourceMappingURL=backbone-min.map.
After downloading the missing file (the link comes from here), the error disappeared.
I had the same problem. I tried to disable the extensions one by one to check it, and finally realized I had Adblock enabled, which was causing this issue. To remove that error I followed the step below,
Three dots (top right corner).
Click More tools --> extensions.
Disable the Adblock.
Reload the page.
And it should work now.
DevTools failed to load source map: Could not load content for chrome-extension://cfhdojbkjhnklbpkdaibdccddilifddb/browser-polyfill.js.map: System error: net::ERR_FILE_NOT_FOUND
Disable the Chrome extension "Adblock Plus - free ad blocker". https://chrome.google.com/webstore/detail/adblock-plus-free-ad-bloc/cfhdojbkjhnklbpkdaibdccddilifddb
Lately this error is caused by the extension.
Problems with Debugging and Sourcemaps in Web Browsers
Hope this clarifies the technicals behind the problem...knowing how things works helps some :)
This browser error means it has some compiled version of your JavaScript in a sourcemap intermediate file it or some 3rd party created that is now needed when debugging that same script in "devtools" in your web browser.
This can happen if your script fails (or in your case trying to get an image source hidden in the sourcemap code that created the script) but whose script error is tied to some JavaScript that got created from an original sourcemap file that now cannot be found to debug that same error. So it's an error about an error, a missing debugging file creating a new error. (crazy, huh?)
This error is likely coming from an extension in the web browser and is reporting it has generated a script error it has recorded in the console.log window of devtools (press F12 in the browser). The error is likely from the extension (not your code) saying it has some code that contains an address to a sourcemap file it cannot access, has a bad URI/URL address, is blocked, or that is missing.
The browser only needs this sourcemap file if a developer using devtools will need to debug the original script again.
A sourcemap, by the way, is a file that translates or transpiles code from one language to another language. Often this is a file that the browser uses to translate this source code into a child script like JavaScript/ECMAScript, or when it needs to do the opposite and recreate the source file from the child script. In most cases this file is not needed at all as a 3rd party software program has already compiled or transpiled the source code into the child script for the browser. For example, developers who like TypeScript use it to create JavaScript. This source code gets transpiled into JavaScript so the browser script engine can run it. The URI/URL to this sourcemap file is usually at the top of the javaScript or application compiled code file in a format like //#....
When this intermediary transpile file is missing or blocked for security reasons in a web browser, the application will usually not care unless it needs the source file for debugging the child script using this source file. In that case it will complain when it feels it needs this file and cannot find it, as it uses it to recreate the source file for the code running in the browser when debugging the script in order to allow a developer to debug the original source code. When it cannot find it, it means that any developer trying to debug it will not be able to do so, and is stuck with the compiled code only. So it is safe to turn off these errors in the various ways mentioned in this post. It should not affect your own scripts if it is connected to an extension. Even if it is related to your own scripts, it is still unlikely you need it unless you plan to run debugging from devtools.
In my case, it was JSON Viewer extension that was blocking the source map files from being loaded
In my case i made silly mistake by adding bootstrap.min.js instead of bootstrap.bundel.js :)
You need to open Chrome in developer mode: select More tools, then Extensions and select Developer mode
I'm using a game library (http://html5quintus.com/) to try and make a very simple 2d platformer. I don't think this is necessarily specific to game development though. I'm really just trying to play some audio files.
I'm using FireFox 31.0 - (the latest AFAIK).
The audio files I'm dealing with are all .mp3 files. The line of code that seems to be causing the problem is:
Q.audioContext.decodeAudioData(request.response, function(buffer) {
callback(key,buffer);
}, errorCallback);
The error I get is:
The buffer passed to decodeAudioData contains invalid content which
cannot be decoded successfully. localhost : 50796 uncaught exception:
Error Loading: jump.mp3
What I find most confusing though, is that if I navigate to the audio file directly (/audio/jump.mp3) - FireFox will play that audio file correctly.
Here's where it gets really weird....AFTER I load any one of the .mp3 files. If I navigate back to my game and reload it - it suddenly works completely. All of the sounds/background music work and everything is just like it is in IE and Chrome. But if I don't manually load a .mp3 file first, it doesn't.
Once the game is working, I can close that tab/open a new tab and visit the URL and it works again. It seems to continue working fine until I exit FireFox completely. Then, the game won't work until I first revisit the .mp3 file directly.
Can anyone tell me what I've done wrong here?
In my project the decoding worked fine for months until this morning.
So it's not the audio files, it's not a caching issue, this error only
appears in Firefox (I have v31.0), in other browsers(both desktop and mobile) it works fine.
So I'd bet that it's a Firefox bug, one that unfortunately I don't have a solution for yet.
Will update if I find something.
As a work-around (for FireFox 31); if I add a regular audio tag to my static loading page, when the game engine gets around to loading it's resources, FireFox will accept the .mp3 files.
<audio src="audio/coin.mp3"></audio>
If I include that line everything works on all of the major browsers. If I remove that line, FireFox 30 works, but FireFox 31 fails :( Yuck.
FF25.0, Fedora 18.
This just keeps going round in circles. The staging extension installs, and parts of it are active as the extension modifies a bit of the dom (I think even the background script is running too as the local storage is initialized). Not all of the extension works, such as the sidebar and other dom injection that should run on page load. But the debug mode page in crossrider fails to recognise the running extension.
I suspect this is due to a bug in my code but there appears to be no way to debug it. When I commented out the sidebar, it still showed briefly after another install, which makes me suspect a proxy/cache is getting in the way but adding an extra GET argument on the extension URL didn't help. I've tried adding debugger to extension.js. The console is empty. No errors are reported by firebug. The extension works fine in chrome, and I really don't want to go back to a blank extension and try adding bit by bit till it fails. There must be a simpler way such as making firefox just say, "here's your problem, right on line number X". Any ideas?
[EDIT]
After turning on some debug options, I've got errors in the console, but clicking on the offending file/line number just opens the "Source of:..." window. In google chrome I get the file in the debugger, can hit break points, refresh and catch the error as it happens. Better yet, how about a "break-on-exceptions" option that both works but also actually works.
[EDIT]
I finally got the Browser Debugger working. The first error is a NS_ERROR_XPC_BAD_OP_ON_WN_PROTO.
Well, to start actually getting messages you need to set some flags in "about:config" listed here: Setting_up_extension_development_environment
I'll copy a few...
javascript.options.showInConsole = true (this was already on for me)
browser.dom.window.dump.enabled = true
javascript.options.strict = true (there's also a debug version I turned on too)
devtools.chrome.enabled = true (nothing to do with google chrome)
devtools.debugger.remote-enabled = true (the important one, allowing Firefox->Web Developer->Browser Debugger, make sure to allow the remote debugger otherwise it undoes the config change)
devtools.errorconsole.enabled = true
extensions.logging.enabled = true
It looks like quite a few options have been removed too. This has at least got me started.
[EDIT]
This answer also mentions the "Web Developer->Browser Debugger" (which is currently blank - "no sources" - I have no idea) and "Web Developer->Browser Console" windows (just seems to have the same output as the in-window console).
Throw a giant try/catch around ALL your extension code. At least this allows the crossrider "staging" extension to install and be recognised.
Print the exception (I assume all the stupid about:config stuff has to be set for this to work)
appAPI.ready(function($) {
try {
...rest of extension code
}
catch (e)
{
console.log("#################", e);
}
}
Locate the error in the console, and click on the [object exception]. Note the line number (it won't be correct as other code is injected). Also note we've managed to print an exception and firefox failed to break on it. FFFFFFFFFFFFFFFFFFFF
Add some newlines approximately in the middle of the code.
Reload. Note the line number. If it's changed the error is after the newlines. If not the error is before.
Repeat from step 4 until the error is found.
Take a moment to reflect on the stupidity of this process. (this isn't exactly a comment directed at crossrider, more at the severe lack of simple web development tools and APIs currently available)
We're testing out pdf.js and while it seems like an awesome project we can't get it working in Safari.
(Tested on PDF.JS version = 0.8.229 (latest) / Safari 5.1.9 - 6.0.4 / Mac OSX 10.6.8 - 10.8.3)
EXAMPLE:
This is an example of the demo code served from our server with a sample PDF that works on Chrome/FFox but not Safari:
http://test.appgrinders.com/pdf_js/test.html
Console output:
Warning: Setting up fake worker.
Error: Invalid XRef stream (while reading XRef):
Error: Invalid XRef stream pdf.js:850undefined
Warning: Indexing all PDF objects
Error: Invalid XRef stream (while reading XRef):
Error: Invalid XRef stream pdf.js:850undefined
More tests:
The following is a list of sample PDFs we tested (They were all served from our server, and all worked in Chrome/FFox/Android). The only one that worked with Safari was the PDF file served from the pdf.js project itself:
FAILS IN SAFARI:
http://samplepdf.com/sample.pdf
http://forums.adobe.com/servlet/JiveServlet/previewBody/2041-102-1-2139/Sample.pdf
https://github.com/prawnpdf/prawn/raw/master/data/pdfs/form.pdf
WORKS IN SAFARI:
http://cdn.mozilla.net/pdfjs/helloworld.pdf
(NOTE: This is a sample PDF from the pdf.js project and the only one we ever got working)
We've submitted a bug report, but the developers do not seem to have an answer, so I'm hoping someone here might...
How can we get pdf.js working with Safari?
I've figured out how to get things working on Mac Safari (without necessarily understanding why)...
compatibility.js must be included.
PDFJS.workerSrc must be assigned.
The demo code I had been testing (from the JS Bin demos here)
does not do this, though some other online examples do (including
the hello world example and the examples provided by
#AndrewBenjamin – thanks). Other browsers don't seem to require this,
but Safari won't work without it.
<script type="text/javascript" src="compatibility.js"></script>
<script type="text/javascript" src="pdf.js"></script>
<!-- NEED THIS for Safari Mac to render work -->
<script type="text/javascript">
// Specify the main script used to create a new PDF.JS web worker.
// In production, change this to point to the combined `pdf.js` file.
PDFJS.workerSrc = 'pdf.worker.js';
</script>
Again, can't explain why, but this is how we got it working for us.
I've got PDF.js working fine in Safari on my local server, but when I put it on the remote server, the goofy error comes back:
Warning: Setting up fake worker.
Unhandled rejection: Error: INVALID_STATE_ERR: DOM Exception 11
It will also show this error on my local computer if I happen to have the developer console open. Close the console, PDF displays in Safari; open the console, and it doesn't work anymore.
The question is: what do the developer tools and the remote server change versus running on a local server? Is this still a range-checking problem?
I got PDF.js to work, though! I've modified so much stuff I don't know what part of what I did worked. Here's a list of stuff I did.
Added compatibility.js – modified the last function in it to read like this:
(function checkRangeRequests() {
var isSafari = Object.prototype.toString.call(window.HTMLElement).indexOf('Constructor') > 0;
if (!isSafari) {
return;
}
document.addEventListener('DOMContentLoaded', function (e) {
if (isSafari) {
PDFJS.disableRange = true;
}
});
})();
Changed the order of xhr.open() calls in pdf.js so that xhr.setRequestHeader() occurs after xhr.open()
Removed all 'use strict'; lines
Added xhr.setRequestHeader("Cache-control", "no-cache"); after xhr.open on lines 37272 and 41262
Minified pdf.js and it all works all the time!
PDFJS.getDocument() will accept either a string link or a Uint8Array. In my client side version I pass PDFJS.getDocument() a Uint8Array, but if I want an existing file rendered, I just pass the path to the file:
jspdf line 965:
PDFJS.getDocument('..files/pdf/sample.pdf').then(function(pdf) {
I don't know what makes your safari browser fail, but if you can see sample.pdf on my test site, you have to be very close to solving this.
I've figured out how to get things working on Mac Safari & iPad
I removed the 'strict mode' at the beginning of
1. pdf.js/src/core/worker.js
2. pdf.js/web/download_manager.js
And worked!!
if you're going to support versions below Safari 14, from what I understood PDFjs doesn't support that.
you will need to use an external viewer in an object tag:
<object data="https://drive.google.com/viewerng/viewer?embedded=true&url=https://researchtorevenue.files.wordpress.com/2015/04/1r41ai10801601_fong.pdf&embedded=true"></object>
I had the same problem with Safari Mobile... Can't open more than 1 Mb PDF's... I solved fragmenting the file in parts of 900 kb, join them in local and then injecting to pdf.js as Uint8Array() object. I think it's a no documented limitation.