Let's say we have this code:
<form action='' method='POST' enctype='multipart/form-data'>
<input type='file' name='userFile'><br>
<input type='submit' name='upload_btn' value='upload'>
</form>
which results in this:
When the user clicks the 'Browse...' button, a file search dialog box is opened:
The user will select the file either by double-clicking the file or by clicking the 'Open' button .
Is there a Javascript Event that I can use to be notified after the file is selected?
Listen to the change event.
document.getElementById('input').addEventListener('change', function(e) {
if (e.target.files[0]) {
document.body.append('You selected ' + e.target.files[0].name);
}
});<input type="file" id="input">
<input type="file" onchange="..." />) although this is not recommended.
When you have to reload the file, you can erase the value of input. Next time you add a file, 'on change' event will trigger.
document.getElementById('my_input').value = null;
// ^ that just erase the file path but do the trick
jQuery way:
$('input[name=myInputName]').change(function(ev) {
// your code
});
That's the way I did it with pure JS:
var files = document.getElementById('filePoster');
var submit = document.getElementById('submitFiles');
var warning = document.getElementById('warning');
files.addEventListener("change", function () {
if (files.files.length > 10) {
submit.disabled = true;
warning.classList += "warn"
return;
}
warning.classList -= "warn";
submit.disabled = false;
});#warning {
text-align: center;
transition: 1s all;
}
#warning.warn {
color: red;
transform: scale(1.5);
}<section id="shortcode-5" class="shortcode-5 pb-50">
<p id="warning">Please do not upload more than 10 images at once.</p>
<form class="imagePoster" enctype="multipart/form-data" action="/gallery/imagePoster" method="post">
<div class="input-group">
<input id="filePoster" type="file" class="form-control" name="photo" required="required" multiple="multiple" />
<button id="submitFiles" class="btn btn-primary" type="submit" name="button">Submit</button>
</div>
</form>
</section>Though it is an old question, it is still a valid one.
Expected behavior:
Cancel.Code with a demonstration:
<!DOCTYPE html>
<html>
<head>
<title>File upload event</title>
</head>
<body>
<form action="" method="POST" enctype="multipart/form-data">
<input type="file" name="userFile" id="userFile"><br>
<input type="submit" name="upload_btn" value="upload">
</form>
<script type="text/javascript">
document.getElementById("userFile").onchange = function(e) {
alert(this.value);
this.value = null;
}
</script>
</body>
</html>Explanation:
onchange event handler is used to handle any change in file selection event.onchange event is triggered only when the value of an element is changed. So, when we select the same file using the input field the event will not be triggered. To overcome this, I set this.value = null; at the end of the onchange event function. It sets the file path of the selected file to null. Thus, the onchange event is triggered even at the time of the same file selection.The Change event gets called even if you click on cancel..
