HTML Versus XHTML (REPEATING COMPUTER SCIENCE, July 30, 2021)

I repeat "HTML Versus XHTML" (see W3SCHOOL, https://www.w3schools.com/html/html_xhtml.asp), when I forgot can I use <br> or <br />, and while it may be the same result, but here is explained the difference.

See also how define < and > (W3SCHOOL, https://www.w3schools.com/xml/xml_syntax.asp).

JULY 29, 2021. REPEATING JavaScript

JavaScript has many HTML methods, eg, 'getElementById()':

JavaScript can change HTML content.

Example from Digital Ocean

<p id="demo2"></p>
<script>
const poem = "The Wide Ocean";
const author = "Pablo Neruda";

const favePoem = `My favorite poem is ${poem} by ${author}.`;
document.getElementById("demo2").innerHTML = favePoem;
</script>

Read details: Tania Rascia, July 11, 2017, How To Work with Strings in JavaScript, Digitalocean. Retrieved: July 29, 2021 https://www.digitalocean.com/community/tutorials/how-to-work-with-strings-in-javascript