How to Prevent Page Navigation in JavaScript: Interrupting or Blocking User Actions

Preventing Page Navigation in JavaScript

When navigating away from a web page, users may inadvertently lose unsaved changes or leave important tasks unfinished. JavaScript offers methods to address this by interrupting or preventing page navigation altogether.

Interrupt Navigating:

The onbeforeunload event is triggered when a user attempts to navigate away from a page. This event allows you to display a prompt or message to the user, asking for confirmation or providing additional information. Returning a non-empty string from the onbeforeunload handler will interrupt navigation and prevent the page from leaving.

In modern browsers, returning an empty string from the event handler will display a default confirmation message. This message cannot be overridden. For instance:

<code class="javascript">window.onbeforeunload = function() {
  return "";
}</code>

Example with Custom Message (Older Browsers):

Older browsers provide the option to specify a custom message in the navigation confirmation prompt:

<code class="javascript">window.onbeforeunload = function() {
  return "Are you sure you want to navigate away?";
}</code>

Note: This approach is limited because it requires a specific message to be displayed and may not be compatible with all browsers. It's recommended to use the empty string approach for broader compatibility.

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