Wouldn't `this.type = element[ 0 ].type` do the trick as well?

Still leaves the question what to do if its neither. Currently it ends up with `undefined, causing, for example, to add `ui-undefined-label`.

To address both, how about this?

```js
_readType: function() {
	this.type = this.element[ 0 ].type;
	if ( /radio|checkbox/.test( this.type )) {
		throw new Error( "Can't create checkboxradio widget for type " + this.type );
	}
},
```