如何使用 javascript 将变量设置为链接？

Question

I am making a website that has a course in HTML. Every lesson/page on the website will have the same format because I was trying to set a link in a button to a variable surrounded in quotes. Ex. "document.getElementById("completedLessons").innerHTML = "<a href=\"lesson" + lessonsCompleted + ".html" , then I would set lessonsCompleted to the amount of lessons completed. Then I put the button at the bottom of my code: <p id="completedLessons"></p><button>Start</button></a> . My computer has Chrome OS and doesn't have Linux, so it can't run python, PHP, etc.

Answer 1

<a id='lessonAnchor' href='not a thing yet'>Lesson Anchor<a>
<script>
   document.getElementById('lessonAnchor').href=
      "lesson" + lessonsCompleted + ".html";
</script>