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.
Store a cookie the first time someone visits the page. On refresh check if your cookie exists and if it does, alert.
function checkFirstVisit() {
if(document.cookie.indexOf('mycookie')==-1) {
// cookie doesn't exist, create it now
document.cookie = 'mycookie=1';
}
else {
// not first visit, so alert
alert('You refreshed!');
}
}
and in your body tag:
<body onload="checkFirstVisit()">
Here is a method that is supported by nearly all browsers:
if (sessionStorage.getItem('reloaded') != null) {
console.log('page was reloaded');
} else {
console.log('page was not reloaded');
}
sessionStorage.setItem('reloaded', 'yes'); // could be anything
It uses SessionStorage to check if the page is opened the first time or if it is refreshed.
⚠️⚠️⚠️ 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");
}
source : https://developer.mozilla.org/en-US/docs/Web/API/Navigation_timing_API
if(sessionStorage.reload) {
sessionStorage.reload = true;
// optionnal
setTimeout( () => { sessionStorage.setItem('reload', false) }, 2000);
} else {
sessionStorage.setItem('reload', false);
}
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 <link rel="prerender" href="//example.com/next-page.html">
4: any other method.
I found some information here Javascript Detecting Page Refresh
function UnLoadWindow() {
return 'We strongly recommends NOT closing this window yet.'
}
window.onbeforeunload = UnLoadWindow;