isChanged() {
		return (this.node ? this.node.getAttribute('data-changed') : null) == 'true';
	}
Check whether the input value was altered by the user.

@instance
@memberof LuCI.ui.AbstractElement
@returns {boolean}
Returns `true` if the input value has been altered by the user or
`false` if it is unchanged. Note that if the user modifies the initial
value and changes it back to the original state, it is still reported
as changed.