code: function() {
          if (!this.suspendCheckChange) {
              var me = this,
                  newVal = me.getValue(),
                  oldVal = me.lastValue;
              if (!me.isEqual(newVal, oldVal) && !me.isDestroyed) {
                  me.lastValue = newVal;
                  me.fireEvent('change', me, newVal, oldVal);
                  me.onChange(newVal, oldVal);
              }
          }
      }
docs: Checks whether the value of the field has changed since the last time it was checked.
  If the value has changed, it:
  
  1. Fires the {@link #change change event},
  2. Performs validation if the {@link #validateOnChange} config is enabled, firing the
  {@link #validitychange validitychange event} if the validity has changed, and
  3. Checks the {@link #isDirty dirty state} of the field and fires the {@link #dirtychange dirtychange event}
  if it has changed.