+ * @example
+ * Ext.define('Ext.ux.CustomSpinner', {
+ * extend: 'Ext.form.field.Spinner',
+ * alias: 'widget.customspinner',
+ *
+ * // override onSpinUp (using step isn't neccessary)
+ * onSpinUp: function() {
+ * var me = this;
+ * if (!me.readOnly) {
+ * var val = me.step; // set the default value to the step value
+ * if(me.getValue() !== '') {
+ * val = parseInt(me.getValue().slice(0, -5)); // gets rid of " Pack"
+ * }
+ * me.setValue((val + me.step) + ' Pack');
+ * }
+ * },
+ *
+ * // override onSpinDown
+ * onSpinDown: function() {
+ * var val, me = this;
+ * if (!me.readOnly) {
+ * if(me.getValue() !== '') {
+ * val = parseInt(me.getValue().slice(0, -5)); // gets rid of " Pack"
+ * }
+ * me.setValue((val - me.step) + ' Pack');
+ * }
+ * }
+ * });
+ *
+ * Ext.create('Ext.form.FormPanel', {
+ * title: 'Form with SpinnerField',
+ * bodyPadding: 5,
+ * width: 350,
+ * renderTo: Ext.getBody(),
+ * items:[{
+ * xtype: 'customspinner',
+ * fieldLabel: 'How Much Beer?',
+ * step: 6
+ * }]
+ * });
+ *
+ * By default, pressing the up and down arrow keys will also trigger the onSpinUp and onSpinDown methods;
+ * to prevent this, set `{@link #keyNavEnabled} = false`.