set onclick event for image on Pocket IE

Question

The code works on IE and Firefox but not on Pocket IE on windows mobile. Does anyone have an idea how I can trigger an event when clicking on an image on Pocket IE?

<input type="image" src="img/speaker.png" onclick="alert('bla')">

I also tried

<img src="img/speaker.png" onclick="alert('bla')"/>

does not work either.