How to check if input file is empty in jQuery

Just check the length of files property, which is a FileList object contained on the input element

if( document.getElementById("videoUploadFile").files.length == 0 ){
    console.log("no files selected");
}

Here is the jQuery version of it:

if ($('#videoUploadFile').get(0).files.length === 0) {
    console.log("No files selected.");
}