file tag validation

HTML

<input type="file" placeholder="Video file" class="dupFile" id="gl_video_file">

JavaScript

$('body').on('change', '#gl_video_file', function(e) {
               var glVideoFiles = event.target.files;
                glVideoFileSplit = glVideoFiles[0].name.split(".");
                glVideoFileFormat = glVideoFileSplit[1];
                glVideoFileName = glVideoFileSplit[0].split(' ').join('_')
                //alert ("File name : "+glVideoFileName)
                
                if (!glVideoFileName.match(/^[a-z0-9_-]+(\.mp4)$/i)) {
                  alert('First check : Bad file name format.');
                }
                if (!($('#gl_video_file').val()).match(/^[a-z0-9_-]+(\.jpg)$/i))    {
                  alert('Second check : Bad file name format.');
                }
    
                    if (this.files[0].size > maxFileSize) {
                      alert("File size is too big.");
                     }
    
   
            });