code: function( element ) {
  			var cleanElement = this.clean( element ),
  				checkElement = this.validationTargetFor( cleanElement ),
  				result = true;
  
  			this.lastElement = checkElement;
  
  			if ( checkElement === undefined ) {
  				delete this.invalid[ cleanElement.name ];
  			} else {
  				this.prepareElement( checkElement );
  				this.currentElements = $( checkElement );
  
  				result = this.check( checkElement ) !== false;
  				if (result) {
  					delete this.invalid[checkElement.name];
  				} else {
  					this.invalid[checkElement.name] = true;
  				}
  			}
  			// Add aria-invalid status for screen readers
  			$( element ).attr( "aria-invalid", !result );
  
  			if ( !this.numberOfInvalids() ) {
  				// Hide error containers on last error
  				this.toHide = this.toHide.add( this.containers );
  			}
  			this.showErrors();
  			return result;
  		}
docs: http://jqueryvalidation.org/Validator.element/