difference between id and class in html with example

Example 1: difference between id and class in css

/* The difference between an ID and a class is that an ID 
is only used to identify one single element in our HTML. 
IDs are only used when one element on the page should have a 
particular style applied to it. However,
a class can be used to identify more than one HTML element. */

Example 2: how to call an id in css

<style>
  #selector {
  color: red;
}
/* # is id selector */
</style>


<div id="selector">
<p>This is an id</p>
</div>