Edo.controls.PercentSpinner = function(){ Edo.controls.PercentSpinner.superclass.constructor.call(this); }; Edo.controls.PercentSpinner.extend(Edo.controls.Spinner,{ minValue: 0, maxValue: 100, _setText: function(v){ v += '%'; Edo.controls.PercentSpinner.superclass._setText.call(this, v); } }); Edo.controls.PercentSpinner.regType('percentspinner');