difference between class and id in css code 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: css class id

css
.class
#id