Check if page gets reloaded or refreshed in JavaScript

Question

I want to check when someone tries to refresh a page.

For example, when I open a page nothing happens but when I refresh the page it should display an alert.

Answer 1

?????? window.performance.navigation.type is deprecated, pls see Илья Зеленько's answer

---

A better way to know that the page is actually reloaded is to use the navigator object that is supported by most modern browsers.

It uses the Navigation Timing API.

//check for Navigation Timing API support
if (window.performance) {
  console.info("window.performance works fine on this browser");
}
console.info(performance.navigation.type);
if (performance.navigation.type == performance.navigation.TYPE_RELOAD) {
  console.info( "This page is reloaded" );
} else {
  console.info( "This page is not reloaded");
}