Try this:
<script language="javascript" type="text/javascript">
var videoHelpUrl = '@Url.Action("Index", "Help", new { Id = 46 })';
console.log(videoHelpUrl);
</script>
console.log will output the Url.
Note: Always keep in mind that everything following @ in a Razor view will be processed by the Razor engine. This is why you can surround @Url.Action(...) with quotes. It will be processed first by Razor engine and then by Javascript when it is executed.