revision:
The toLowerCase() method converts a string to lowercase letters. It does not change the original string.
string.toLowerCase()
Parameters: none
<p>toLowerCase() converts a string to lowercase letters:</p>
<p id="demo"></p>
<script>
let text = "Hello World!";
let result = text.toLowerCase();
document.getElementById("demo").innerHTML = result;
</script>
<div>
<p id="local-1"></p>
<p id="local-2"></p>
</div>
<script>
let text = "Hello World!";
document.getElementById("local-1").innerHTML = "text : " + text;
let result = text.toLowerCase();
document.getElementById("local-2").innerHTML = "text to lower case : " + result;
</script>