Loadspeed theme improvements for Wordpress -> functions.php

functions.php

// Remove query strings from urls
function remove_query_strings( $src ) {
	$src = remove_query_arg( array( 'v', 'ver', 'rev', 'bg_color', 'sensor' ), $src );
	return $src;
}
add_filter( 'style_loader_src', 'remove_query_strings', 10, 2 );
add_filter( 'script_loader_src', 'remove_query_strings', 10, 2 );


// Defer parsing of JavaScripts
function defer_parsing_js( $url ) {
	if ( ! is_admin() ) {
		if ( false === strpos( $url, '.js' ) ) {
			return $url;
		}
		if ( strpos( $url, 'jquery.js' ) ) {
			return $url;
		}
		if ( strpos( $url, 'slick.min.js' ) ) {
			return $url;
		}
		if ( strpos( $url, 'custom.js' ) ) {
			return $url;
		}
		if ( strpos( $url, 'functions.min.js' ) ) {
			return $url;
		}
		if ( strpos( $url, 'jquery.bxslider.min.js' ) ) {
			return $url;
		}
		return "$url' defer='defer";
	} else {
		return $url;
	}
}
add_filter( 'clean_url', 'defer_parsing_js', 10, 1 );