Automatically choose file for website upload based on last submission? - javascript

So, I am on a 'competitive coding' website which requires me to manually select a file ("choose file") to submit to the online testing grader. I was wondering, since there are a multitude of extensions on chrome that allow me to auto-fill a form option, is there a way to automatically fill the "choose file" button when submitting a code file based on the last file I chose when clicking that same "choose file" button webpage?

Unfortunately JS can't help here. For security reasons, it is not possible to manually add and upload a file in a file input control with JavaScript.
The reason behind this is that webpages would be able to upload files from someone's computer, so long as they knew the path.
What you could do as a last resort would be using a third party software that would register mouse clicks for you and emulate a real user acting on the interface.

You cannot do that since this input type cannot be prefilled, here is a trick though :
What you can do is having an hiden collection of text inputs containing the base64 of the files you load using your form.
When a user selects a file, just use btoa() and atob() methods to base64-it and store it in this hidden form input
If you want to 'preset' some files, just fill your list of base64 and simply display a kind of placeholder to show that you have a file 'already appended'
Then in your script when form is submitted, work with the list of base64 instead of the actual values from the input type file

Related

Laravel 6 Multiple File preview with remove

I want to ask,
so I have a form whose contents one of which is to upload multiple files, then after I browse the file, then the file will appear (preview),
then the user will have access to choose the file to upload when it is not wanted then there is a delete button for wrong one file.
then after all okay, then the form will be uploaded.
then after that the user will be able to edit the file again through another page without deleting the old file.
this is what I want,
user fills in the input form
when in the input file field, the user can select several files
Then after clicking OK, the selected file will be displayed
The user can delete one of the unwanted files
after all okay the user submit the form to db
like the display on wetransfer
can anyone teach me?

How to edit css when file is uploaded

I have a form where users can upload a file. The uploading and validation afterwards (filesize, filetype...) is done with php by submitting.
But I wonder how I could give the user a "visual feedback" that his file was "picked" immediately. So I don't need validation nor anything complex. I just want to either color the label green or rename the label of the upload field when the user has selected a file and clicked "Choose" in his browser.
How would I do that most easily?
On success assign one variable then use that variable to add class to the element.

Download file that we have browse using input type file multiple - Javascript

I have code that you can input multiple file using input type file multiple, which is a basic html5.
When you click the input file, you browse the file that you want (can be multiple), it will show you the list of files that you have input with remove button for each item, so you can remove it for each item.
Now the problem is I want to enhance it with download button.
Anybody knows how to add download file from input type file function using javascript ?
Thank you so much

Button to show choose a file to upload dialog box

Instead of using an input type="file" html tag, is it possible to bring up a choose a file to upload dialog box by clicking a input type="button"? Then when a file is selected from the choose a file to upload dialog box, the file path gets inserted into a regular html input type="text" tag?
I've seem that gmail does something similar but not with buttons and text inputs, they simply have a link add file or something like that. When that link is clicked, it shows the select file(s) to upload by mail.google.com dialog box. When a file is clicked, the file name is shown on the screen.
How are they doing that?
<input type="file" style="display:none;" id="inputfile"/>
try this
Try this one. I think it is useful.. :)
I think most browsers have this locked down for security purposes. Buttons and text boxes can be manipulated via JavaScript. File input boxes cannot, and for good reason; imagine if a javascript could open a dialog, set the path to a sensitive file on your system, then simulate the button click to download the file!
By the way, if you are looking to style it, perhaps this would work: http://www.quirksmode.org/dom/inputfile.html
Check this fiddle: http://jsfiddle.net/A4BS7/1/
NOTE:
a) This may not work well on older browsers (mainly IE) that don't fire the change event on the file input.
b) For the upload to work as expected, you'll need to include the <input type="file"> element in your form. The text element can be used for displaying the selected file at best.
It is not possible to alter an input[type=file] as you like, it is a purely native form element.
Besides you won't be able to get the path to the file for security reasons. Old IE versions shows the path but it is not the case anymore with newer versions and you won't be able to do anything with the path on server-side anyway.
There are though some methods to style:
Styling File Upload / Select Input Control
Styling an input type="file"
Styling file inputs with CSS and the DOM
Have a look at plupload, I've used it many times to handle file uploading.

asp file upload control custom text

So I want to use a <asp:FileUpload> control to "upload" a picture.
I dont really upload the picture, I just want to get it's inputstream so I can change it to a byte array and place it in the database.
However when I add a <asp:FileUpload> it comes with a static button and text field. Thou I like the textfield, I want to change the text of the button because my site is full english and the button's text changes depending on.. well something with the language of the browser or OS.
So I searched on google for a while and fould some info about making a html control
<input type='button' style='visibility: hidden'> and make another button which activates the file button by using javascript.
So here's the problem, when I add runat=server to the hidden file button I can't "find" it anymore using the document.getElementById javascript function and thus can not get the inputstream or the file.
What i'm asking is if there isn't a simple way to change the text of a <asp:FileUpload> so I can still use that control. If not, could you please show me a way how I can get the hidden file button to work with code behind and get it's inputstream?
Have a look at blog post Styling an input type="file" by Peter-Paul Koch. You may try Ajax AsyncFileUpload control or use uploadify jQuery plug-ins too.

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