NS_ERROR_NOT_AVAILABLE: Component returned failure code: 0x80040111 (NS_ERROR_NOT_AVAILABLE) [nsIDOMWindow.alert]

This is a common error in Firefox. It is logged in console when you try to call on non existent DOM API method. Seeing this error message is very common with methods call to alert(), confirm(), drawImage() (canvas) and window.open(). You may think "how those methods could be 'non-existent'?", since they are standard APIs of the window object. Well, that's true, they can't, but consider the case when browser blocks your alert or pop-up windows. Firefox pop-up blocker will make those methods not available in that context and should silently carry on with the next statement, but instead it throws an error.

To solve this problem:

  • make sure you are calling methods on non-null objects;
  • remove alert(), confirm() or open() methods in unload event handler. FF pop-up blocker ignores all window.open() methods in the unload handler.

The flavours of the error message:

  • NS_ERROR_NOT_AVAILABLE: Component returned failure code: 0x80040111 (NS_ERROR_NOT_AVAILABLE) [nsIDOMWindow.alert]
  • NS_ERROR_NOT_AVAILABLE: Component returned failure code: 0x80040111 (NS_ERROR_NOT_AVAILABLE) [nsIDOMWindow.confirm]
  • NS_ERROR_NOT_AVAILABLE: Component returned failure code: 0x80040111 (NS_ERROR_NOT_AVAILABLE) [nsIDOMCanvasRenderingContext2D.drawImage]

At the time of writing the problem has not been fixed.

Dynamically change <title> using jQuery

In this post I will show how to dynamically change document's title using JavaScript and jQuery. Browsing the web (and StackOverflow) I saw a lot of posts that say you can't do it using jQuery. Actually, there is a jQuery syntax that is basically a wrapper for javascript code (see below).

Note: just to clarify, by document title we mean the text that is displayed in the browser window or a tab.

The best way to change the document title is to use native javascript api document.title.

document.title = "New text set by JavasSript";

The equivalent jQuery code of js code above.

$(document).prop('title', 'New text set by jQuery');


Let's say we need to change the tab title text when a user clicks on a button. Here is a jQuery code to do just that:

  <title>Initial page title</title>
  <script src="path-to/jquery.js"></script>
        document.title = $(this).val();
        // jQuery syntax alternative
        // $("title").text( $(this).val() );
  <input type="button" id="clickme" name="clickme" value="Click me!" />

To conclude, you are better off using document.title, because it is cross-browser and has performs better.

Alternative jQuery syntax has been tested in all major browsers.