diff --git a/wp-includes/class.wp-scripts.php b/wp-includes/class.wp-scripts.php
index 0ac2af4d97..f75929b4ab 100644
--- a/wp-includes/class.wp-scripts.php
+++ b/wp-includes/class.wp-scripts.php
@@ -110,7 +110,7 @@ class WP_Scripts extends WP_Dependencies {
 		}
 
 		$this->print_extra_script( $handle );
-		if ( !preg_match('|^https?://|', $src) && ! ( $this->content_url && 0 === strpos($src, $this->content_url) ) ) {
+		if ( !preg_match('|^(https?:)?//|', $src) && ! ( $this->content_url && 0 === strpos($src, $this->content_url) ) ) {
 			$src = $this->base_url . $src;
 		}
 
diff --git a/wp-includes/class.wp-styles.php b/wp-includes/class.wp-styles.php
index 48e8f7ef1d..fdfe5afe32 100644
--- a/wp-includes/class.wp-styles.php
+++ b/wp-includes/class.wp-styles.php
@@ -135,7 +135,7 @@ class WP_Styles extends WP_Dependencies {
 	}
 
 	function _css_href( $src, $ver, $handle ) {
-		if ( !is_bool($src) && !preg_match('|^https?://|', $src) && ! ( $this->content_url && 0 === strpos($src, $this->content_url) ) ) {
+		if ( !is_bool($src) && !preg_match('|^(https?:)?//|', $src) && ! ( $this->content_url && 0 === strpos($src, $this->content_url) ) ) {
 			$src = $this->base_url . $src;
 		}