How can restrict user to upload max 10 files at once?

Question

I am using <input type="file" multiple="multiple"> in my web page to upload files (using ajaxupload). It will allow user to upload multiple files at once. But I want to restrict user to select only 10 files at a time not more than that.

How can I achieve this?

Answer 1

<input id="files" type="file" name="files[]" multiple="multiple" onchange="checkFiles(this.files)">

function checkFiles(files) {       
    if(files.length>10) {
        alert("length exceeded; files have been truncated");

        let list = new DataTransfer;
        for(let i=0; i<10; i++)
           list.items.add(files[i]) 

        document.getElementById('files').files = list.files
    }       
}

This function will not allow to select files more than 10.

Answer 2

this piece of code does what you desire and also stops the form from being submitted.

<script>
    $(function() {
        $("button[type = 'submit']").click(function(event) {
            var $fileUpload = $("input[type='file']");
            if (parseInt($fileUpload.get(0).files.length) > 10) {
                alert("You are only allowed to upload a maximum of 10 files");
                event.preventDefault();
            }
        });
    });
</script>