VBScript and Dart were a thing, but they were vendor-specific. Netscape had Javascript Style Sheets in the 90s, where you get the full power of a PL for styling. Then you had Java and Flash through plugins, but they weren't first class citizens with the DOM. However, Sun and Netscape did originally intend Java to be embedded in Netscape alongside JS, but it didn't happen, so Java went the plugin route.

People have tried, but getting the rest of the world to agree is the hard part.