Very useful Javascript feature that can prevent a user from losing the data they are entering in an entry field or text editor in case of unintentional leaving of a page.
Gmail predicts which emails might be of high importance to you so it marks them as important with a yellow icon. If your inbox ends up full of so called important emails, this is how you disable this feature.
We will learn how we can write SQL command to show data from two tables and also specify some additional conditions to limit the amount of data returned.