src/Tag.php
public function addClass($class)
    {
        if (! $this->hasClass($class)) {
            $this->set('class', trim((string) $this->get('class') . ' ' . $class));
        }

        return $this;
    }
public function addClass($class)
    {
        if (! $this->hasClass($class)) {
            $this->set('class', trim((string) $this->get('class') . ' ' . $class));
        }

        return $this;
    }
public function addClass ( $ class ) { if ( ! $ this -> hasClass ( $ class ) ) { $ this -> set ( 'class' , trim ( ( string ) $ this -> get ( 'class' ) . ' ' . $ class ) ) ; } return $ this ; }
Add a class to the element's class list

@param string $class

@return self
Add a class to the element s class list