How can I set the value of this?
<input type="file" />
You cannot set it to a client side disk file system path, due to security reasons.
Imagine:
<form name="foo" method="post" enctype="multipart/form-data">
<input type="file" value="c:/passwords.txt">
</form>
<script>document.foo.submit();</script>
You don't want the websites you visit to be able to do this, do you? =)
You can only set it to a publicly accessible web resource as seen in this answer, but this is clearly not the same as a client side disk file system path and it's therefore useless in that context.
You can't.
The only way to set the value of a file input is by the user to select a file.
This is done for security reasons. Otherwise you would be able to create a JavaScript that automatically uploads a specific file from the client's computer.
Not an answer to your question (which others have answered), but if you want to have some edit functionality of an uploaded file field, what you probably want to do is:
show the current value of this field by just printing the filename or URL, a clickable link to download it, or if it's an image: just show it, possibly as thumbnail
the <input> tag to upload a new file
a checkbox that, when checked, deletes the currently uploaded file. note that there's no way to upload an 'empty' file, so you need something like this to clear out the field's value
You can't. And it's a security measure. Imagine if someone writes JS that sets file input value to some sensitive data file?
I have write full example for load URL to input file, and preview
you can check here
1
https://vulieumang.github.io/vuhocjs/file2input-input2file/
in short you can use this function
function loadURLToInputFiled(url){
getImgURL(url, (imgBlob)=>{
// Load img blob to input
// WIP: UTF8 character error
let fileName = 'hasFilename.jpg'
let file = new File([imgBlob], fileName,{type:"image/jpeg", lastModified:new Date().getTime()}, 'utf-8');
let container = new DataTransfer();
container.items.add(file);
document.querySelector('#file_input').files = container.files;
})
}
// xmlHTTP return blob respond
function getImgURL(url, callback){
var xhr = new XMLHttpRequest();
xhr.onload = function() {
callback(xhr.response);
};
xhr.open('GET', url);
xhr.responseType = 'blob';
xhr.send();
}
As everyone else here has stated: You cannot upload just any file automatically with JavaScript.
HOWEVER! If you have access to the information you want to send in your code (i.e., not C:\passwords.txt), then you can upload it as a blob-type, and then treat it as a file.
What the server will end up seeing will be indistinguishable from someone actually setting the value of <input type="file" />. The trick, ultimately, is to begin a new XMLHttpRequest() with the server...
function uploadFile (data) {
// define data and connections
var blob = new Blob([JSON.stringify(data)]);
var url = URL.createObjectURL(blob);
var xhr = new XMLHttpRequest();
xhr.open('POST', 'myForm.php', true);
// define new form
var formData = new FormData();
formData.append('someUploadIdentifier', blob, 'someFileName.json');
// action after uploading happens
xhr.onload = function(e) {
console.log("File uploading completed!");
};
// do the uploading
console.log("File uploading started!");
xhr.send(formData);
}
// This data/text below is local to the JS script, so we are allowed to send it!
uploadFile({'hello!':'how are you?'});
So, what could you possibly use this for? I use it for uploading HTML5 canvas elements as jpg's. This saves the user the trouble of having to open a file input element, only to select the local, cached image that they just resized, modified, etc.. But it should work for any file type.
You need to create a DataTransfer and set the .files property of the input.
const dataTransfer = new DataTransfer();
dataTransfer.items.add(myFile);//your file(s) reference(s)
document.getElementById('input_field').files = dataTransfer.files;
the subject is very old but I think someone can need this answer!
<input type="file" />
<script>
// Get a reference to our file input
const fileInput = document.querySelector('input[type="file"]');
// Create a new File object
const myFile = new File(['Hello World!'], 'myFile.txt', {
type: 'text/plain',
lastModified: new Date(),
});
// Now let's create a DataTransfer to get a FileList
const dataTransfer = new DataTransfer();
dataTransfer.items.add(myFile);
fileInput.files = dataTransfer.files;
</script>
Define in html:
<input type="hidden" name="image" id="image"/>
In JS:
ajax.jsonRpc("/consulta/dni", 'call', {'document_number': document_number})
.then(function (data) {
if (data.error){
...;
}
else {
$('#image').val(data.image);
}
})
After:
<input type="hidden" name="image" id="image" value="/9j/4AAQSkZJRgABAgAAAQABAAD/2wBDAAgGBgcGBQgHBwcJCQgKDBQNDAsLDBkSEw8U..."/>
<button type="submit">Submit</button>
Actually we can do it.
we can set the file value default by using webbrowser control in c# using FormToMultipartPostData Library.We have to download and include this Library in our project. Webbrowser enables the user to navigate Web pages inside form.
Once the web page loaded , the script inside the webBrowser1_DocumentCompleted will be executed.
So,
private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
FormToMultipartPostData postData =
new FormToMultipartPostData(webBrowser1, form);
postData.SetFile("fileField", #"C:\windows\win.ini");
postData.Submit();
}
Refer the below link for downloading and complete reference.
https://www.codeproject.com/Articles/28917/Setting-a-file-to-upload-inside-the-WebBrowser-com
I have a simple web app that I am needing someone to select a .pdf from a file server and then display that .pdf on the web page.
I can get the user to select the .pdf via something like <input type="file" id="myFile">
I can also embed a .pdf into an iframe to display on the web app nicely with <iframe src="//path/to/file.pdf" width="100%" height="500px"></iframe>
But how do I display the .pdf the user selected from the input? Is there a way I can pass the value of the input into the src of the iframe? Can I open the .pdf in a new tab or a new html file so I don't have to refresh the entire page?
For anyone needing help with this I found a solution that worked for me.
I created an input for the file I'm wanting to upload. This input calls a JS function that is defined below.
<input type="file" id="file-open" onchange="previewFile()" hidden="hidden" accept=".pdf"><br>
Then created an iframe with size I wanted
<iframe src="" id="iframe-pdf" width="1200px" height="800px"></iframe>
Finally I used JavaScript to convert the file to base64 and use FileReader to open the file within the iframe
function previewFile() {
const preview = document.querySelector('iframe');
const file = document.querySelector('input[type=file]').files[0];
const reader = new FileReader();
var filename = file.name;
reader.addEventListener("load", function () {
// convert file to base64 string
preview.src = reader.result;
}, false);
if (file) {
reader.readAsDataURL(file);
}
}
</script>
So im making a website, and one of its core features I need to get working is getting the web page to export a mundane .txt file containing all the content from the forms I have.
Once that works, I also need to figure out how to import that same file back into the website and have it automatically fill in the text boxes.
How can I go about doing this?
Your question is kind of broad and doesn't show much research effort on your part. It's good form to have a go and then come here when you run into a problem, rather than just ask us to solve your problem for you. Despite that, I'll try to give you some pointers. :)
I recently had a requirement to make a button to download the contents of a div. I made a gist for future reference. You can probably adapt it to your purpose.
Basically what I did was assign a click handler to a HTML button marked 'Download'. When the button is clicked, I create a temporary anchor element on the page and set its href to the contents of the div and then programmatically click on the anchor to fire the download and finally removing the temporary anchor from the page. There's a fallback for Internet Explorer with a different method. I adapted this code from an SO answer some time ago.
var downloadButton = document.getElementById('downloadButton');
downloadButton.addEventListener('click', function () {
//get the contents of the div
var contents = document.getElementById('someDiv').innerHTML;
if (contents.length = 0) {
return;
}
var filename = 'some-filename.txt';
if (navigator.msSaveBlob) { // IE
navigator.msSaveBlob(new Blob([contents], { type: 'text/plain;charset=utf-8;' }), filename);
} else {
var link = document.createElement('a');
link.setAttribute('download', filename);
link.setAttribute('href', 'data:text/plain;charset=utf-8,' + encodeURIComponent(contents));
document.body.append(link);
link.click();
document.body.removeChild(link);
}
});
As for your next requirement, upload the file and importing the data, I'll direct you to the HTML5 Rocks - file handling tutorial.
I just had a crack at a quick file uploader and I have it dumping the file contents to the console. You could, instead, parse the file contents and add the data back to your form elements as required. Here's my test code:
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-type" content="text/html; charset=utf-8" />
<title>Test Page</title>
<script>
function handleFileSelect(evt) {
var files = evt.target.files; // FileList object
// Loop through the FileList
for (var i = 0; i < files.length; i++) {
var reader = new FileReader();
// when the file has been read, print the contents to the console
reader.onloadend = function (evt) {
if (evt.target.readyState == FileReader.DONE) {
console.log(evt.target.result);
}
};
var text = reader.readAsText(files[i]);
}
}
document.addEventListener('DOMContentLoaded', function () {
document.getElementById('files').addEventListener('change', handleFileSelect, false);
});
</script>
</head>
<body>
<input type="file" id="files" name="files[]" multiple />
</body>
</html>
I'm trying to download a dynamically generated file from the server using a hidden form.
Below is the angular function that I'm using to submit the hidden form
$scope.downloadCsv = function() {
var dataset = JSON.stringify($scope.dataset);
var body = $('body');
var reportParamJson = angular.toJson($scope.dataset);
var hiddenForm = "<form action='/Reports/SaveTestCsv' method='POST' target='_blank'><input type='hidden' name='dataset' value='" + dataset + "'/ ><button id='submitCSV' type='submit'></button></form>";
body.append(hiddenForm);
$('#submitCSV').click();
}
Below is the .net mvc method to generate the response with the file
[HttpPost]
public ActionResult SaveTestCsv(string dataset)
{
var data = JsonConvert.DeserializeObject<MyObject>(dataset);
var binary = getTestCSV(data);
var file = File(binary, "text/csv", "test.csv");
return file;
}
Below is the relevant html code from the partial html page that I'm including in the view using ng-include
<div>Download CSV</div>
<div ng-grid="gridOptions"></div>
.
When I click on "Download CSV", Chrome, FF and IE10 prompts me to save the file without refreshing the page/view, but on IE8/9, the page is refreshed, so the content from the ng-include tag is gone, in particular the html I posted above is no longer present.
I'm wondering if this has something to do with the hashbang in the url from IE8/9 and is there any way to fix this?
Edit
I ended up removing routing from angular completely and just use .net MVC to do the routing for me, and then it's working on IE8
In this code for the PDF reader pdf-js there is an input tag to let the user upload an input file
<input id="fileInput" class="fileInput" type="file" oncontextmenu="return false;" style="visibility: hidden; position: fixed; right: 0; top: 0" />
This input tag is not a part of any form. Once the user uploads the file, where does it go? Where is the code that processes the file? (I'm asking in general, not necessarily specific to this piece of code.)
"Then it's interesting. This code doesn't have server side"
No, It doesn't.
Pdf.js is a client side program that written with javascript. So that works on javascript side.
It actually takes the file that you wanna show, and does whatever must be done like converting the buffer to Uint8Array than renders it.
All processes happen on javascript side. No server side, no file upload.
Here is an article about reading local files in javascript
Here is the related part of code in pdf.viewer.js
window.addEventListener('change', function webViewerChange(evt) {
var files = evt.target.files;
if (!files || files.length === 0)
return;
// Read the local file into a Uint8Array.
var fileReader = new FileReader();
fileReader.onload = function webViewerChangeFileReaderOnload(evt) {
var buffer = evt.target.result;
var uint8Array = new Uint8Array(buffer);
PDFView.open(uint8Array, 0);
};
var file = files[0];
fileReader.readAsArrayBuffer(file);
PDFView.setTitleUsingUrl(file.name);
// URL does not reflect proper document location - hiding some icons.
document.getElementById('viewBookmark').setAttribute('hidden', 'true');
document.getElementById('download').setAttribute('hidden', 'true');
}, true);