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
See the error on my website here
I have embedded a blazor app in my jekyll site. It runs perfectly locally, but when I publish it on github pages, I am getting this error:
Failed to find a valid digest in the 'integrity' attribute for resource 'https://chrisevans9629.github.io/blazor/xt/_framework/wasm/dotnet.3.2.0-rc1.20222.2.js' with computed SHA-256 integrity 'yVt8FYsTQDifOGsifIkmEXwe+7ML0jZ1dMi2xluiDXQ='. The resource has been blocked.
This is something that I think blazor generates when the page is ran. this is what my page looks like that starts blazor:
<script src="js/index.js"></script>
<app>Loading...</app>
Built with <3 using Blazor
<script src="_framework/blazor.webassembly.js"></script>
This is what the page looks like on github pages:
<script src="js/index.js"></script>
<app>Loading...</app>
<p>Built with <3 using Blazor
<script src="_framework/blazor.webassembly.js"></script></p>
<script type="text/javascript">var Module; window.__wasmmodulecallback__(); delete window.__wasmmodulecallback__;</script><script src="_framework/wasm/dotnet.3.2.0-rc1.20222.2.js" defer="" integrity="sha256-iZCHkFXJWYNxCUFwhj+4oqR4fkEJc5YGjfTTvdIuX84=" crossorigin="anonymous"></script></body>
Why is this error happening and how can I fix this? I've thought about create a script that would remove the integrity attribute, but I don't think that would be a good solution.
I found an answer here
Cause
Because I am using github pages to host my blazor app, it's using git to push up the code. Git by default will try to normalize line endings when committing code, which was causing the integrity of the blazor app to fail due to the files changing.
Solution
To fix this, I added a .gitattributes file to my blazor folder with * binary as the contents.
This tells git to treat all files as binary and therefore not to normalize the line endings. After I did that, I had to delete my _framework folder in my blazor app and rebuild it. After doing this, the blazor app worked.
In case someone else ends up here with the issue I had today..
I also got this error on a Blazor Wasm app locally after simple modification, and then still appeared after reverting changes.
The solution for me was to do a clean and rebuild.
In my case, it was a wrong target framework in the publish profile - I should not have selected win-x64.
I'm not sure of the exact reason, but the server interferes in some way with the response, based on the target framework. Just select browser-wasm and redeploy; it should be fine.
I spent too much time on this issue. Clean and Rebuild does not work for me.
What worked for me is deleting bin and obj folders from the Client(Blazor WASM) Project.
Environment
.Net 5 and 6
Visual Studio 2019 and 2022
Just to leave here a note on something I came across while trying to figure out what was going on.
If for some reason you removed the service worker from your app and the resources were actually cached in the common http cache, there is a possibility that once you re-enable the service worker you will get this error, because the service worker will pick up the http cached version and not the server's.
What I did was to add cache: "no-cache" to the Request's init.
So my onInstall now looks something like this
async function onInstall(event) {
console.info('Service worker: Install');
// Fetch and cache all matching items from the assets manifest
const assetsRequests = self.assetsManifest.assets
.filter(asset => offlineAssetsInclude.some(pattern => pattern.test(asset.url)))
.filter(asset => !offlineAssetsExclude.some(pattern => pattern.test(asset.url)))
.map(asset => new Request(asset.url, { integrity: asset.hash, cache: "no-cache" }));
// Also cache authentication configuration
assetsRequests.push(new Request('_configuration/TestApp.Client'));
await caches.open(cacheName).then(cache => cache.addAll(assetsRequests));
}
It looks like hash generated inside ServiceWorkerAssetsManifest for all the files and on the client side don't match. It looks like ServiceWorkerAssetsManifest is not generating hash again when the file is modified, specially the static files.
Had the same problem today, in my case the error came with a css file.
The problem was that I had two versions of my application deployed to local folders.
At first I started the old version, closed it and then opened up the new version.
It seems that the old css file was cached in the browser which caused the error to appear.
The fix was simply pressing CTRL + U to open up the index.html file, clicking on the css file which caused the error and press F5 to reload the file. This solved the error for me.
A better solution!
Open service-worker.js
change
.map(asset => new Request(asset.url, { integrity: asset.hash }));
to :
.map(asset => new Request(asset.url));
Now it works!
I Had this same issue and none of these solutions worked for me, but they set me on the right path. I am deploying mine to my local machine and using IIS for testing purposes, and I found that in the publish profile that I have created in Visual Studio 2022, the check box to "Remove additional files at destination" was not checked and as soon as I checked this and republished it, everything worked fine. I must have removed a file that was being published in a previous build and it was still there since it wasn't being deleted by any subsequent builds/publishes. But this solved it for me, it might
As this answer suggested, I want to modify a little bit office.js.
So I copied the content of https://appsforoffice.microsoft.com/lib/1/hosted/office.js to local, such that https://localhost:3000/static/office.js shows well the content.
Then, I make a very simple file test.html:
<html>
<head>
<!--<script src="https://appsforoffice.microsoft.com/lib/1/hosted/office.js"></script>-->
<script type="text/javascript" src="https://localhost:3000/static/office.js"></script>
</head>
<body>
haha
</body>
</html>
Loading https://localhost:3000/static/test.html with remote office.js in a browser shows Warning: Office.js is loaded outside of Office client
o15apptofilemappingtable.js:11, and loading it in an Office add-in works well.
However, loading https://localhost:3000/static/test.html with local office.js in a browser shows Uncaught SyntaxError: Unexpected token <
o15apptofilemappingtable.js:1, and loading it in an Office add-in gives an error Add-in Error Something went wrong and we couldn't start this add-in. Please try again later or contact your system administrator.
So does anyone know what's wrong here? Is it possible to make our own local version of office.js?
See my answer in the linked question. Essentially, no, you should not be making your own local copy of "office.js". But if you did want a local copy -- which we already offer on NuGet and, more recently, on NPM (https://www.npmjs.com/package/#microsoft/office-js) -- you would need all the associated files in that directory as well, not just Office.js itself.
See https://unpkg.com/#microsoft/office-js#1.1.1/dist/ for a listing of the files and folders that make up Office.js. Not all (in fact, not most) are used in any given session, but you do want the whole set of files since different ones are loaded in different circumstances.
I'm getting a "Resource interpreted as Script but transferred with MIME type text/plain" warning in Google Chrome when including a local script file.
I know the problem appears when loading a file from a server or through ajax which most often depends on wrong headers being set.
The weird thing is that I get this warning even though it is run from a local folder: file:///C:/test/foo.html
This happens only in Chrome with the most basic html there is:
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="bar.js"></script>
</head>
<body>
</body>
</html>
bar.js is also as simple as it can get:
function hello() {}
I've tried adding a meta tag:
<meta http-equiv="content-script-type" content="text/javascript">
and tested with other doctypes but nothing seems to help.
This obviously isn't a real issue since the scripts still work fine, but I'm working on a large project and currently have around 150 scripts included. It therefore makes it difficult to see when an actual warning occurs in between them.
Everything works fine when I run the file on a server, locally or remote.
Any ideas on why chrome is annoying me with this?
I figured it out!
The Visual Studio installer must have added an errant line to the registry.
open up regedit and take a look at this registry key:
See that key? The Content Type key? change its value from text/plain to text/javascript.
Finally chrome can breathe easy again.
I should note that neither Content Type nor PercievedType are there by default on Windows 7, so you could probably safely delete them both, but the minimum you need to do is that edit.
Anyway I hope this fixes it for you too!
I tried fixing this problem using this method but it didn't work for me.
My problem was that IIS manager didn't have MIME types in HTTP Features.
I was able to turn it on by enabling Static Context via...
--> Control Panel
--> Programs
--> Turn Windows features on or off
--> Internet Information Services
--> World Wide Web Services
--> Common HTTP features
--> [X] Static Content.
After this, MIME types appeared and everything started working again.
The accepted answer is a great one! However, just to post an answer for those who encounter problem like me, who use a department/college computer sometimes, where I do not have the permission to change any key value in regedit.
Change
<script type="text/javascript" src="main.js"></script>
to
<script src="main.js"></script>
Although the error message still exist, the page loaded correctly.