How to validate a file upload field using Javascript/jquery

Question

How can I validate if the user has selected a file to upload?

Edit: bumped

Answer 1

Simple and powerful way(dynamic validation)

place formats in array like "image/*"

var upload=document.getElementById("upload");
var array=["video/mp4","image/png"];
upload.accept=array;
upload.addEventListener("change",()=>{

console.log(upload.value)
})