public static function attr( $attr = array() ) {
		$buffer = " ";
		foreach( $attr as $key => $value ) {
		
			switch( $key ) {
		
				case 'class':
				if ( is_array( $value ) ) { $value = implode( ' ', $value ); }
				break;
		
				case 'style':
				if ( is_array( $value ) ) {
					$style = $value; $value = "";
					foreach( $style as $k => $v ) {
						$value .= $k.':'.$v.';';
					}
				}
				break;
			}
		
			$buffer .= $key.'="'.$value.'" ';
		}
		
		return substr( $buffer, 0, -1 );
	}