Making 'file' input element mandatory (required) - html

Question

I want to make (an HTML) 'file' input element mandatory: something like
<input type='file' required = 'required' .../>
But it is not working.
I saw this WW3 manual which states 'required' attribute is new to HTML 5. But I am not using HTML 5 in the project I am working which doesn't support the new feature.
Any idea?

Answer 1

Thanks to HTML5, it is as easy as this:
<input type='file' required />
Example:
<form>
<input type='file' required />
<button type="submit"> Submit </button>
</form>

Answer 2

You can do it using Jquery like this:-
<script type="text/javascript">
$(document).ready(function() {
$('#upload').bind("click",function()
{
var imgVal = $('#uploadfile').val();
if(imgVal=='')
{
alert("empty input file");
return false;
}
});
});
</script>
<input type="file" name="image" id="uploadfile" size="30" />
<input type="submit" name="upload" id="upload" class="send_upload" value="upload" />

Answer 3

As of now in 2017, I am able to do this-
<input type='file' required />
and when you submit the form, it asks for file.

Answer 4

You could create a polyfill that executes on the form submit. For example:
/* Attach the form event when jQuery loads. */
$(document).ready(function(e){
/* Handle any form's submit event. */
$("form").submit(function(e){
e.preventDefault(); /* Stop the form from submitting immediately. */
var continueInvoke = true; /* Variable used to avoid $(this) scope confusion with .each() function. */
/* Loop through each form element that has the required="" attribute. */
$("form input[required]").each(function(){
/* If the element has no value. */
if($(this).val() == ""){
continueInvoke = false; /* Set the variable to false, to indicate that the form should not be submited. */
}
});
/* Read the variable. Detect any items with no value. */
if(continueInvoke == true){
$(this).submit(); /* Submit the form. */
}
});
});
This script waits for the form to be submitted, then loops though each form element that has the required attribute has a value entered. If everything has a value, it submits the form.
An example element to be checked could be:
<input type="file" name="file_input" required="true" />
(You can remove the comments & minify this code when using it on your website)

Answer 5

var imgVal = $('[type=file]').val();
Similar to Vivek's suggestion, but now you have a more generic selector of the input file and you don't rely on specific ID or class.
See this demo.

Answer 6

Some times the input field is not bound with the form.
I might seem within the <form> and </form> tags but it is outside these tags.
You can try applying the form attribute to the input field to make sure it is related to your form.
<input type="file" name="" required="" form="YOUR-FORM-ID-HERE" />
I hope it helps.

Answer 7

All statements above are entirely correct. However, it is possible for a malicious user to send a POST request without using your form in order to generate errors. Thus, HTML and JS, while offering a user-friendly approach, will not prevent these sorts of attacks. To do so, make sure that your server double checks request data to make sure nothing is empty.

Answer 8

https://www.geeksforgeeks.org/form-required-attribute-with-a-custom-validation-message-in-html5/
<button onclick="myFunction()">Try it</button>
<p id="geeks"></p>
<script>
function myFunction() {
var inpObj = document.getElementById("gfg");
if (!inpObj.checkValidity()) {
document.getElementById("geeks")
.innerHTML = inpObj.validationMessage;
} else {
document.getElementById("geeks")
.innerHTML = "Input is ALL RIGHT";
}
}
</script>