Visual Studio Code, find javascript definition in html script-tag

I'm working on a web project in VSC with html,js and css-files (nothing special). Some javascript file are defined in a tag in html-file:

<script type="text/javascript">
var myvar01 = true;
var myvar02 = false;
var myvar03 = "var99";
</script>

Variable myvar01 is used in a js-file. If I highlight this variable in the js-file and call function "Go to Definition" (context menu), the definition in the html-file is not found. Why? Both files are open in the editor.