×

Save Your Code

If you click the save button, your code will be saved, and you get an URL you can share with others.

By clicking the "Save" button you agree to our terms and conditions.

Report Error

×

Save to Google Drive

If you have a Google account, you can save this code to your Google Drive.

Google will ask you to confirm Google Drive access.

×

Open from Google Drive

If you have saved a file to Google Drive, you can open it here:

Result Size: 625 x 571
x
 
<!DOCTYPE html>
<html>
<body>
<h1>The Storage Event</h1>
<p>The Storage event is triggered when there is a change in the window's storage area.</p>
<p><strong>Note:</strong> The storage event is only triggered when a window 
<strong>other than itself</strong> makes the changes.</p>
<p>Therefore, in this example, a new window is created, and the changes is done in the new window.</p>
<h1>The oldValue Property</h1>
<p>The oldValue property belongs to the Storage Event object, and returns the old value of the item that was changed.</p>
<button onclick="changeValue()">Change a Storage Item</button>
<p id="demo"></p>
<script>
window.addEventListener("storage", myFunction);
function myFunction(event) {
  var txt = "Key: " + event.key + "<br>";
  txt += "Old Value: " + event.oldValue + "<br>";
  txt += "New Value: " + event.newValue;
  document.getElementById("demo").innerHTML = txt;
}
function changeValue() {
  var x = window.open("", "myWindow", "width=200,height=100");
  x.localStorage.setItem("mytime", Date.now());
  x.close();
}
</script>
</body>
<!-- Mirrored from www.w3schools.com/jsref/tryit.asp?filename=tryjsref_event_storage_oldvalue by HTTrack Website Copier/3.x [XR&CO'2014], Mon, 27 Jan 2020 03:17:04 GMT -->
</html>
×

Report a Problem: