LibWeb: Don't prepare script when src attribute is removed

Author: https://github.com/tcl3
Commit: 08b5cae199
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3658
Reviewed-by: https://github.com/gmta ✅

Libraries/LibWeb/HTML/HTMLScriptElement.cpp

@@ -64,6 +64,11 @@ void HTMLScriptElement::attribute_changed(FlyString const& name, Optional<String
         if (namespace_.has_value())
             return;
 
+        // AD-HOC: This ensures that prepare_script() is not called when the src attribute is removed.
+        //         See: https://github.com/whatwg/html/pull/10188/files#r1685905457 for more information.
+        if (!value.has_value())
+            return;
+
         // 2. If localName is src, then run the script HTML element post-connection steps, given element.
         post_connection();
     } else if (name == HTML::AttributeNames::async) {