how can you retrieve the data from a document with javascript that isn't the page you are on if you have the url of the new document.
what i am trying to do is create a page that has a text field for providing a local file name and a button that retrieves the words from the document provided.
thanks.
HTML5 has a File API that lets you read local files. It's supported in at least Firefox (3.6 and later, I think) and Chrome. I don't know if any other browsers support it yet or not. If you need to support other browsers, you'll have to fall back to something like Flash, but I don't have any experience with that.
Unfortunately, by default Chrome doesn't allow local files to access other local files (each file is considered to be from its own domain). You can explicitly allow it by adding the --allow-file-access-from-files flag when you launch Chrome.
Here's a good introduction to the File API with several examples: http://www.html5rocks.com/en/tutorials/file/dndfiles/.
Browser security does not allow direct access to the local filesystem. If it could, web pages would be able to steal any file of your machine.
HTML5 local storage does allow local access, but on a different principle.
Related
I am developing a tab pane app in Excel which needs to read the current document. In Word, the Office JavaScript API has the method Office.context.document.getFileAsync(), but this is not available in Excel.
I can get the URL of the document with Office.context.document.getFileProperties(), and then I thought I could read the file with this.
I tried using the HTML5 FileReader() object, but this only works for files selected from the file input control. I tried manipulating a hidden file input control so it automatically uses the current document, but JavaScript understandably prevents you from doing this for security reasons. I could ask the user to browse to the document they are currently using but that would be a poor user experience.
So I tried using ActiveXObject('Scripting.FileSystemObject') but ActiveX is not allowed in tab pane apps at all, whatever the current security setting are in IE.
What other options do I have?
According to the API road map, Office.context.document.getFileAsync() is not available in Excel at this moment.
I don't think it's feasible by using getFilePropertiesAsync(). It only returns the URL. Usually browser forbids developer touching any content in the file system. Therefore, it's hard to access the local file system in JavaScript code.
Besides, the file may not be in local file system. For example, it could be hosted in Onedrive or SharePoint. getFilePropertiesAsync() should return its real URL in Onedrive/SharePoint, instead of local file system.
I guess Microsoft will support getFileAsync() in the future.
I have developed a script for myself to read and process local text and csv files on my computer using recent Chrome or Firefox browsers with the filereader api. The script will work on the computer, even though it is not connected to the internet or a local webserver.
The reasoning behind this is to have a standalone text file interrogator, which will work on almost any computer, requiring only a browser to execute and display reasonably formatted output. similar to an awk type application.
I use the filereader api and it works well.
I do not properly understand the workings of the browser, so my question may be very stupid.
Is it possible that my script can somehow pass the filename to the script filereader api, without having to choose a file from input type=file field.
eg I have a file called addresses.csv and it resides in the same directory as my html/js file with the filereader api code.
I want to simulate the choosing of a file, without accessing my local directory and without using a webserver, but a dropdown box of predefined filenames would be even better.
No, for security reasons its not possible, because otherwise people could open arbitrary files on the computers of their visitors which is definitely not intended.
This specification also assumes that the primary user interaction is with the element of HTML forms [HTML], and that all files that are being read by FileReader objects have first been selected by the user.
See http://www.w3.org/TR/FileAPI/#security-discussion
No you cannot. Javascript cannot read your local filesystem without the use of a file input or drag and drop files (html5) as it would be vulnerable to malicious use.
There was a start of a filesystem api which Chrome has included. But you cannot read/write to just any place you want on the filesystem, you can only do so to a sandboxed area on the filesystem. Wither or not they will continue to have this in future versions of Chrome though I do not know.
It also appears the W3C itself has discontinued the file system api
I am creating 2 HTML files that will be stored an an iPhone locally and accessed through a WebView.
I am wondering if it is possible to set localStorage in one file, and get the results of the storage from the other file.
I know that localStorage is accessible from files on the same domain, however, it appears that you can not get the value from a different local file?
I have also tried running this in Safari on the desktop with local files and the same issue occurs.
When you are opening the files locally, i.e. using the file:// protocol, as of now the browsers can not determine what is "same domain" so every file is considered a separate domain. Thus you can not use localStorage when you're opening the files.
Here is some more information on the problem in FireFox: https://bugzilla.mozilla.org/show_bug.cgi?id=507361 . Personally I couldn't find much about Safari on this topic.
You can also look over this: Javascript/HTML Storage Options Under File Protocol (file://) . It might be helpful in your situation.
At this time, local files rendered via WKWebView on iOS 10 share access to the "same domain" with respect to localStorage. Unclear whether this is by design or a bug, however.
is there a way to allow a domain access a file which is stored on my computer?
I wish to inject javascript a tag into a website, with the source as a file stored on my computer. This works within a local test.html page, but not when trying to run the script on an actual domain.
Is there a way to set this up my changing window's host file?
Edit - it MUST work in IE
Clarification :: I wish to use javascript injection (using the javascript: protocol) to manipulate the DOM within IE, this is fine. There is however an 8k byte limit within the address bar, which isn't enough. Therefore I wish to store it within a local file on my computer.
Instead of storing it on your computer you could store it online and then load the Javascript through a much smaller amount of code in the address bar.
It's explained how to do this here
http://www.javascriptkit.com/javatutors/loadjavascriptcss.shtml
Try the file API if you're on a recent browser. https://developer.mozilla.org/en/using_files_from_web_applications
If not and you're on IE, you should be able to do it with ActiveX but it'll always ask for permission.
Is it possible to edit a local file without uploading to the browser?
Let's say the client has an HTML file, I want him to be able to use my site's javascript to edit the file without uploading it. Would this be possible?
Thanks.
Yes, it is possible, but only in HTML5 (and only as browsers add support for it...not all do yet), you can find the HTML5 File API here.
Note that the user has to give permission to access the file, from Section 5.9:
Once a user has given permission, user agents should provide the ability to read and parse data directly from a local file programmatically.
Nope, that's not possible and shouldn't be either due to security concerns it may pose otherwise.
Note: This feature is there in HTML5 as pointed out by #Nick Craver, you may want to go for but you should be aware of the fact that HTML5 isn't yet supported by all browsers.