Validation of File Upload Control using jquery

Question

How to validate asp.net FileUpload control using jquery. I need to validate two things, FileUpload should not be empty when user clicks ok button and it should contain only excel and csv files.

please help.

Answer 1

You could validate on extension...

$('form').submit(function(event) {
   var file = $('input[type=file]').val();       

   if ( ! file) {
       alert('The file is required.');
       event.preventDefault();
       return;
   } 

   if (file.match(/\.(?:csv|xl)$/)) {
       alert('CSV or Excel files only!');
       event.preventDefault();
   }

});

...or you could validate on mime type.

$('form').submit(function(event) {
   var file = $('input[type=file]').prop('files')[0];

   if ( ! file) {
       alert('The file is required.');
       event.preventDefault();
       return;
   } 

   var mime = file.type;

   if (mime != 'text/csv' || mime != 'application/vnd.ms-excel') {
       alert('CSV or Excel files only!');
       event.preventDefault();
   }

});

Of course, you need to validate on the server too, this code is just a courtesy to JavaScript enabled users.

Also, choose something better than alert(). They are not the most user friendly way of reporting an error.

Answer 2

You can make the jQuery validation plugin to do that for you:

$(document).ready(function() {
    $("#form").validate({
        rules: {
            MyFile: {
                required: false,
                accept: "jpg|jpeg|png|gif"
            }
        }
    });

    $("#submit").click(function() {
        var file = $('#MyFile').val();

        if($("#create_form").valid()) {
            if(file != '') {
               // do something
            }
        }
    });
});