如何使用 JavaScript 清除 HTML 文件输入？

Question

I want to clear the file input in my form.

I know about setting the sources to the same method... But that method wont erase the selected file path.

Note : I would like to avoid having to reload the page, reset the form or perform an AJAX call.

Is this possible?

Answer 1

There's 3 ways to clear file input with javascript:

1. set value property to empty or null.

   Works for IE11+ and other modern browsers.

2. Create an new file input element and replace the old one.

   The disadvantage is you will lose event listeners and expando properties.

3. Reset the owner form via form.reset() method.

   To avoid affecting other input elements in the same owner form, we can create an new empty form and append the file input element to this new form and reset it. This way works for all browsers.

I wrote a javascript function. demo: http://jsbin.com/muhipoye/1/

function clearInputFile(f){
    if(f.value){
        try{
            f.value = ''; //for IE11, latest Chrome/Firefox/Opera...
        }catch(err){ }
        if(f.value){ //for IE5 ~ IE10
            var form = document.createElement('form'),
                parentNode = f.parentNode, ref = f.nextSibling;
            form.appendChild(f);
            form.reset();
            parentNode.insertBefore(f,ref);
        }
    }
}

Answer 2

tl;dr : For modern browsers, just use

input.value = '';

---

Old answer:

How about:

input.type = "text";
input.type = "file";

I still have to understand why this does not work with webkit .

Anyway, this works with IE9>, Firefox and Opera.
The situation with webkit is that I seem to be unable to change it back to file.
With IE8, the situation is that it throws a security exception.

Edit: For webkit, Opera and firefox this works, though:

input.value = '';

(check the above answer with this proposal)

I'll see if I can find a nice cleaner way of doing this cross-browser without the need of the GC.

Edit2:

try{
    inputs[i].value = '';
    if(inputs[i].value){
        inputs[i].type = "text";
        inputs[i].type = "file";
    }
}catch(e){}

Works with most browsers. Does not work with IE < 9, that's all.
Tested on firefox 20, chrome 24, opera 12, IE7, IE8, IE9, and IE10.

Answer 3

Setting the value to '' does not work in all browsers.

Instead try setting the value to null like so:

document.getElementById('your_input_id').value= null;

EDIT: I get the very valid security reasons for not allowing JS to set the file input, however it does seem reasonable to provide a simple mechanism for clearing already selecting output. I tried using an empty string but it did not work in all browsers, NULL worked in all the browsers I tried (Opera, Chrome, FF, IE11+ and Safari).

EDIT: Please note that setting to NULL works on all browsers while setting to an empty string did not.

Answer 4

Unfortunately none of the above answers appear to cover all the bases - at least not with my testing with vanilla javascript.

• .value = null appears to work on FireFox, Chome, Opera and IE11 (but not IE8/9/10)

• .cloneNode (and .clone() in jQuery) on FireFox appears to copy the .value over, therefore making the clone pointless.

So here is the vanilla javascript function I have written that works on FireFox (27 and 28), Chrome (33), IE (8, 9, 10, 11), Opera (17)... these are the only browsers currently available to me to test with.

function clearFileInput(ctrl) {
  try {
    ctrl.value = null;
  } catch(ex) { }
  if (ctrl.value) {
    ctrl.parentNode.replaceChild(ctrl.cloneNode(true), ctrl);
  }
}

The ctrl parameter is the file input itself, so the function would be called as...

clearFileInput(document.getElementById("myFileInput"));

Answer 5

SOLUTION

The following code worked for me with jQuery. It works in every browser and allows to preserve events and custom properties.

var $el = $('#your-input-id');
$el.wrap('<form>').closest('form').get(0).reset();
$el.unwrap();

DEMO

See this jsFiddle for code and demonstration.

LINKS

• Clearing <input type='file' /> using jQuery

• How to reset file input with JavaScript

Answer 6

document.getElementById('your_input_id').value=''

Edit:
This one doesn't work in IE and opera, but seems to work for firefox, safari and chrome.

Answer 7

U need replace it with new file input. Here is how it can be done with jQuery:

var inputFile = $('input[type=field]');
inputFile.wrap('<div />');

and use this line when you need to clear input field (on some event for example):

inputFile.parent().html( inputFile.parent().html() );

Answer 8

the input.value = null is a working method, however it will only trigger input's change event if called from an onclick event.

Solution to that would be calling that onchange handler manually whenever you need to reset the input.

function reset_input(input) {
    $(input)[0].value = null;
    input_change_handler();
}
function input_change_handler() {
    // this happens when there's been a change in file selection

    if ($(input)[0].files.length) {
        // file(s) selected
    } else {
        // nothing is selected
    }
}
$(input).on('change', input_change_handler);

Answer 9

这其实很容易。

document.querySelector('#input-field').value = '';

Answer 10

I was having same problem and i came up with this.

 var file = document.querySelector('input'); var emptyFile = document.createElement('input'); emptyFile.type = 'file'; document.querySelector('button').onclick = function(){ file.files = emptyFile.files; }

 <input type='file'> <button>clear</button>

Answer 11

I have been looking for simple and clean way to clear HTML file input, the above answers are great, but none of them really answers what i'm looking for, until i came across on the web with simple an elegant way to do it :

var $input = $("#control");

$input.replaceWith($input.val('').clone(true));

all the credit goes to Chris Coyier .

 // Referneces var control = $("#control"), clearBn = $("#clear"); // Setup the clear functionality clearBn.on("click", function(){ control.replaceWith( control.val('').clone( true ) ); }); // Some bound handlers to preserve when cloning control.on({ change: function(){ console.log( "Changed" ) }, focus: function(){ console.log( "Focus" ) } });

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <input type="file" id="control"> <br><br> <a href="#" id="clear">Clear</a>

Answer 12

This worked for me.

const clear = (event) =>{event.target.value = [ ];}
clear("input_id"); 

Answer 13

Try this easy and it works

let input = elem.querySelector('input[type="file"]');
input.outerHTML=input.outerHTML;

this will reset the input

Answer 14

Here are my two cents, the input files are stored as array so here is how to null it

document.getElementById('selector').value = []

this return an empty array and works on all browsers

Answer 15

The above answers offer somewhat clumsy solutions for the following reasons:

1. I don't like having to wrap the input first and then getting the html, it is very involved and dirty.

2. Cross browser JS is handy and it seems that in this case there are too many unknowns to reliably use type switching (which, again, is a bit dirty) and setting value to ''

So I offer you my jQuery based solution:

$('#myinput').replaceWith($('#myinput').clone())

It does what it says, it replaces the input with a clone of itself. The clone won't have the file selected.

Advantages:

1. Simple and understandable code
2. No clumsy wrapping or type switching
3. Cross browser compatibility (correct me if I am wrong here)

Result: Happy programmer

Answer 16

What helped me is, I tried to fetch and upload the last selected file using a loop, instead of clearing out the queue, and it worked. Here is the code.

for (int i = 0; i <= Request.Files.Count-1; i++)
{
 HttpPostedFileBase uploadfile = files[i];
 Stream fs = uploadfile.InputStream;
 BinaryReader br = new BinaryReader(fs);
 Byte[] imageBytes = br.ReadBytes((Int32)fs.Length);
}

Hope this might help some.

Answer 17

I tried most of solutions but did not seem anyone to work. However I found a walk around for it below.

The structure of the form is: form => label , input and submit button . After we choose a file, the filename will be shown by the label by doing so manually in JavaScript.

So my strategy is: initially the submit button is disabled, after a file is chosen, the submit button disabled attribute will be removed such that I can submit file. After I submit, I clear the label which makes it look like I clear the file input but actually not. Then I will disable the submit button again to prevent from submitting the form.

By setting the submit button disable or not, I stop the file from submitted many times unless I choose another file.

Answer 18

I changed to type text and back to type to file using setAttribute

'<input file-model="thefilePic" style="width:95%;" type="file" name="file" id="filepicture" accept="image/jpeg" />'

'var input=document.querySelector('#filepicture');'

if(input != null)
{
    input.setAttribute("type", "text");
    input.setAttribute("type", "file");
}

Answer 19

An - in my world easy an clean solution - is, to set the file inputs files to a clear FileList .

EDIT: as SteJ told - this ist not working with Safari.

Since we can not create a FileList directly - I user DataTransfer as "hack"

@$input[0].files=new DataTransfer().files 

or

file_input_node.files=new DataTransfer().files 

Answer 20

I want to clear the file input in my form.

I know about setting the sources to the same method... But that method wont erase the selected file path.

Note : I would like to avoid having to reload the page, reset the form or perform an AJAX call.

Is this possible?