If you apply the ToggleButton widget to a button, a type attribute is not applied to the rendered node. This applies both to the button tag and the input tag with type="button". As a result, a submit
button is rendered, as this is the default type for the button tag.

This is not a desired behaviour, especially with a toggle button, where you want to add some specific functionality by listening to "pressedChange" events, and not submit the form.

I fixed this by setting the type attribute in a custom renderUI function, but I assume that this should be default behaviour.

var button3 = new Y.ToggleButton({

        srcNode:'#button3'

      });

      button3.renderUI = function() {

        this.get('contentBox').setAttribute("type", 'button');

      };

      button3.render();