TLDR; I need a component that show text that changes frequently but the text should not be part of the HTML-Dom.

If I use a span-element like this

<span>09:45:36</span>

The Text is part of the HTML-Code. I need a component that represent text but is not part of the HTML-Code.

I could use a <input >, style it like a span-element and change the .value using javascript.

<input id="a">
<script>
  window.setInterval(function(){
    document.getElementById('a').value = new Date();
  }, 1000);
</script>

The .value will not be represented in the HTML-Dom. Unfortunately the boundary-size of the input is fixed and does not correlate to the text-size of the field.

Question

What html-tag could I use that shows text without having the text be part of the HTML and size with text?