Simple click on the input activates the event "DOMSubtreeModified"

I'm using this code:

document.body.addEventListener('DOMSubtreeModified', function () {            
    document.title = 'Editar Material *';
    formChanged = true;
}, false);

To check for changes in the various forms and possible images to edit. The problem I encountered was this: just a click on a :input to trigger the event.

Is it possible to ignore the simple click on the :input field without any changes? I know there are more correct ways to do check forms changes, but I need to use something like this.