问使用jQuery验证上传时的文件大小

EN

 <script type="text/javascript">
        $(document).ready(function () {
        $('#AdmissionUpload').on('change', function() {
            // Maximum file size allowed
            var maxFileSize = 20 // 20kb
            // Load the file upload controller to a variable
            var fileUpload = $('#AdmissionUpload');
            //Check if the file upload controller has value
            if (fileUpload.val() == '') {
                return false;
            } else {
                //Check if the file size is less than maximum file size
                if (fileUpload[0].files[0].size < maxFileSize) {
                    return true;
                } else {
                    alert('File size should be less than 20kb')
                    fileUpload.val('');
                    return false;
                }
            }
        });
        })

    </script>