I'm building a small mobile web application using JQuery Mobile. Now I want to select an image on the phone and get information about it so I can upload it later from the app. Is this at all possible?
I might be in an offline situation and should still be able to select a image I want to upload.
If your target phone's browser supports file upload input type and FileAPI (e.g. iOS 6.0 Safari)
<input type="file" name="image" accept="image/*" capture>
then you can let your user pick an existing file, or even use camera to take a shot, and read some attributes of an image file (file name, size, type, modification date).
$("input[type=file]").change(function(){
var file = $("input[type=file]")[0].files[0];
alert(file.name + "\n" +
file.type + "\n" +
file.size + "\n" +
file.lastModifiedDate);
});
You can also make a preview of a chosen file using FileReader.
<div id="preview"></div>
displayAsImage3(file, "preview");
function displayAsImage3(file, containerid) {
if (typeof FileReader !== "undefined") {
var container = document.getElementById(containerid),
img = document.createElement("img"),
reader;
container.appendChild(img);
reader = new FileReader();
reader.onload = (function (theImg) {
return function (evt) {
theImg.src = evt.target.result;
};
}(img));
reader.readAsDataURL(file);
}
}
Here is working jsFiddle
Related
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 like to use JSFiddle when designing a new interface because I find it convenient for various tools within. I'm working on the front end of a site where I want to use a video, and unlike an image, I cant just throw it up on imgur and link to it for free instant hosting while I fiddle with the interface design.
So I want to know if I can somehow use a local file on my PC as the source for an HTML video element hosted on a live site. Obviously this is trivial to do with a web project being worked on on my Desktop, but I'm not sure it can be done on a live test.
For example this would work on a page I open from my desktop, living on my PC:
<video id="Video-Player">
<source src="../movie.mp4" type="video/mp4"/>
</video>
But I don't know whether I can do the equivalent with a page living on the web.
Here's how to allow a user to select an image from their local machine. This should get you started in the right direction.
Add a file input button in the HTML
<input type="file" id="file-btn"/>
and the corresponding handler
document.getElementById('file-btn').addEventListener('change', function(e){
readFiles(e.target.files);
})
Then the code to read the files
function readFiles(files){
files = [].slice.call(files); //turning files into a normal array
for (var file of files){
var reader = new FileReader();
reader.onload = createOnLoadHandler(file);
//there are also reader.onerror reader.onloadstart, reader.onprogress, and reader.onloadend handlers
reader.readAsDataURL(file);
}
}
Now, I've only done this with images, but this is how I read the image data.
function createOnLoadHandler(file){
console.log('reading ' + file.name + ' of type ' + file.type)
function onLoad(e){
var data = e.target.result
display(data);
}
return onLoad
}
function display(data){
var img = document.createElement('img');
img.src = data;
var context = canvas.getContext('2d')
context.clearRect(0, 0, WIDTH, HEIGHT);
context.drawImage(img, 0, 0, WIDTH, HEIGHT);
}
Here is a demo of the above code.
As a side note, if you try to read images from another domain you'll run into cross origin policy issues. I would think the same problem exists for videos as well.
Good day
I am reading HTML files from an external server via JQuery AJAX call, and storing them on a local IOS 6.0 device with FileWriter. I then read the locally stored files with FileReader and I successfully get the text. What I want to achieve from here, is to take the HTML content from the locally stored file (retrieved via FileReader), and push it into the local Safari Browser on the phone for displaying the HTML page (current target market is iPhone 5). Below is some code. Any ideas how to achieve this? I have tried window.open after installing the InAppBrowser plugin (which I do not really want to use because I want to use Safari) and also returning the text in the onloadend event... document.write is also not ideal as I want to open the file in a new window/tab so that it can be closed to direct the user back to the app when done. I am also not sure if I should read as Binary or Text (assuming TEXT would be the right option because it is not a media file)
Please note that I am new to PhoneGap so my methods used may not reflect Best Practice...
document.addEventListener('deviceready', onDeviceReady, false);
function onDeviceReady () {
var fileName = 'some_file.html';
readerObject.setFileName(fileName);
//Instantiate reader on the file
window.requestFileSystem(LocalFileSystem.PERSISTENT, 0,
readerObject.gotFS, readerObject.fail);
}
// Create reader
var readerObject = {
// Sets the file name to read from
setFileName : function(fileName) {
readerObject.fileName = fileName;
},
// Gets the file name to read from
getFileName : function() {
return readerObject.fileName;
},
// Capture the file system
gotFS : function(fileSystem) {
fileSystem.root.getFile(readerObject.getFileName(), null,
readerObject.gotFileEntry, readerObject.fail);
},
gotFileEntry : function(fileEntry) {
fileEntry.file(readerObject.readData, readerObject.fail);
},
**readData : function(file) {
var reader = new FileReader();
reader.onloadend = function(evt) {
//Return text for streaming into the browser (NOT WORKING)
//return evt.target.result;
//Capture file path
var filePath = file.fullPath+"/"+file.name;
//Open file in new window (NOT WORKING)
//window.open(filePath, '_blank', 'location=yes');
window.open("file:///"+filePath, '_blank', 'location=yes');
};
reader.readAsText(file);
//reader.readAsBinaryString(file);
},**
fail : function(error) {
alert(error.code);
}
}
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);
This question already has answers here:
Limit file format when using <input type="file">?
(12 answers)
Closed 7 years ago.
How can someone limit the files that can be selected with the input type="file" element by extensions?
I already know the accept attribute, but in chrome it does limit the files by the last MIME Type defined (in this case "gif") and FF4 does not even limit anything.
<input type="file" accept="image/jpg, image/gif">
Am I doing anything wrong or is there another way?
Easy way of doing it would be:
<input type="file" accept=".gif,.jpg,.jpeg,.png,.doc,.docx">
Works with all browsers, except IE9. I haven't tested it in IE10+.
NOTE: This answer is from 2011. It was a really good answer back then, but as of 2015, native HTML properties are supported by most browsers, so there's (usually) no need to implement such custom logic in JS. See Edi's answer and the docs.
Before the file is uploaded, you can check the file's extension using Javascript, and prevent the form being submitted if it doesn't match. The name of the file to be uploaded is stored in the "value" field of the form element.
Here's a simple example that only allows files that end in ".gif" to be uploaded:
<script type="text/javascript">
function checkFile() {
var fileElement = document.getElementById("uploadFile");
var fileExtension = "";
if (fileElement.value.lastIndexOf(".") > 0) {
fileExtension = fileElement.value.substring(fileElement.value.lastIndexOf(".") + 1, fileElement.value.length);
}
if (fileExtension.toLowerCase() == "gif") {
return true;
}
else {
alert("You must select a GIF file for upload");
return false;
}
}
</script>
<form action="upload.aspx" enctype="multipart/form-data" onsubmit="return checkFile();">
<input name="uploadFile" id="uploadFile" type="file" />
<input type="submit" />
</form>
However, this method is not foolproof. Sean Haddy is correct that you always want to check on the server side, because users can defeat your Javascript checking by turning off javascript, or editing your code after it arrives in their browser. Definitely check server-side in addition to the client-side check. Also I recommend checking for size server-side too, so that users don't crash your server with a 2 GB file (there's no way that I know of to check file size on the client side without using Flash or a Java applet or something).
However, checking client side before hand using the method I've given here is still useful, because it can prevent mistakes and is a minor deterrent to non-serious mischief.
Honestly, the best way to limit files is on the server side. People can spoof file type on the client so taking in the full file name at server transfer time, parsing out the file type, and then returning a message is usually the best bet.
function uploadFile() {
var fileElement = document.getElementById("fileToUpload");
var fileExtension = "";
if (fileElement.value.lastIndexOf(".") > 0) {
fileExtension = fileElement.value.substring(fileElement.value.lastIndexOf(".") + 1, fileElement.value.length);
}
if (fileExtension == "odx-d"||fileExtension == "odx"||fileExtension == "pdx"||fileExtension == "cmo"||fileExtension == "xml") {
var fd = new FormData();
fd.append("fileToUpload", document.getElementById('fileToUpload').files[0]);
var xhr = new XMLHttpRequest();
xhr.upload.addEventListener("progress", uploadProgress, false);
xhr.addEventListener("load", uploadComplete, false);
xhr.addEventListener("error", uploadFailed, false);
xhr.addEventListener("abort", uploadCanceled, false);
xhr.open("POST", "/post_uploadReq");
xhr.send(fd);
}
else {
alert("You must select a valid odx,pdx,xml or cmo file for upload");
return false;
}
}
tried this , works very well