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

I have wrote this function to check both methods using old window.performance.navigation and new performance.getEntriesByType("navigation") in same time:

function navigationType(){

    var result;
    var p;

    if (window.performance.navigation) {
        result=window.performance.navigation;
        if (result==255){result=4} // 4 is my invention!
    }

    if (window.performance.getEntriesByType("navigation")){
       p=window.performance.getEntriesByType("navigation")[0].type;

       if (p=='navigate'){result=0}
       if (p=='reload'){result=1}
       if (p=='back_forward'){result=2}
       if (p=='prerender'){result=3} //3 is my invention!
    }
    return result;
}

Result description:

0: clicking a link, Entering the URL in the browser's address bar, form submission, Clicking bookmark, initializing through a script operation.

1: Clicking the Reload button or using Location.reload()

2: Working with browswer history (Bakc and Forward).

3: prerendering activity like

4: any other method.