How to add js script?

Question

JavaScript

Code start:

window.onload=function(){
document.querySelector("input").oninput = function(){

If you connect the script directly, then everything works. If you connect through an external file, then the script does not work. What could be the problem? In window.onload?

Answer 1

the problem is not from window, try this:

document.querySelector('input').addEventListener("input", myFunc);
function myFunc() {
    // code here
}