My mac air won't switch off

You might need to force quit Safari. Before asking you why, here is how to do it:

Click the Apple in the upper left, then Force Quit. Select safari and do it.

So, how come it's necessary? Strange website? Hmm.

There are several ways to do this as I have found:-

1. Press and hold the OFF button to power down. Then press it again to start and select Cancel to avoid restarting the programmes being run.

2. Disconnect the power and allow the Air battery to completely discharge. This shuts down the Air and you can then add power back and switch on.

3. As LousyFool stated there is the Force Quit option in the Apple icon drop down (or on the double click of the icon in the toolbar if the applicaiton is not responding).

Wow. Shall I guess what the content was? 😉