code: function( e ) {
        // Reset error windows from all elements
        this.reset( FIELDS );
        // Start control each elements
        this.checkFields( e );
        if( e.type !== 'submit' ) return; // if event type is not submit, break
        // This is for when running remote request, return false and wait request response
        else if ( this.handler === 'pending' ) return false;
        // if event type is submit and handler is true, break submit and call onError() function
        else if( this.handler === true ) { this.options.onError.call( this, e ); return false; }
        else return this.options.onValid.call( this, e ); // if form is valid call onValid() function
      }
docs: In this method, fields are validated
  
  @params {object} e : event object
  @return {mixed}