Vue.js Version finding program only returns a white screen

I did write a program to simply display the vue version. Not only i dont get the alert but all I get is a white screen. Im a beginner on javascript and I had installed latest version of nodejs and done programs on it. now I installed vue exactly how the vuejs site has told and it didnt seem to work. I cant find my mistake either but when i try the version of vue on cmd it shows the version correctly

this is my pgm. console log says Vue is not defined.

<html>
 <head>
 <meta charset="utf-8" />
 <script src="https://unpkg.com/vue@next"></script>
 </head>
 <body>
 </body>
 
 <script>
 alert(`Vue.version = ${Vue.version}`);
  </script>
</html>

but when i try it on cmd using
vue --version
i get the correct version