public function hasElement( $name, $prefix = null )
	{
		return isset( $this->elements[ is_null( $prefix ) ? $name : "$prefix:$name" ] );
	}
public function hasElement( $name, $prefix = null )
	{
		return isset( $this->elements[ is_null( $prefix ) ? $name : "$prefix:$name" ] );
	}
public function hasElement ( $ name , $ prefix = null ) { return isset ( $ this -> elements [ is_null ( $ prefix ) ? $ name : "$prefix:$name" ] ) ; }
Return true if a named element exists

@param string $name
@param string $prefix
@return boolean
Return true if a named element exists