javad

i found solution. if anyone have this problem see this article:
http://www.htpcbeginner.com/remove-query-strings-from-static-resources/
and add this code to functions.php:

function _remove_script_version( $src ){
	$parts = explode( '?ver', $src );
        return $parts[0];
}
add_filter( 'script_loader_src', '_remove_script_version', 15, 1 );
add_filter( 'style_loader_src', '_remove_script_version', 15, 1 );

no. just bootstrap’s default js files. actually in GTmetrix I see this error “Remove query strings from static resources”.