Form Validation

JavaScript is usually used for validation input form data before they are sent to the server.

For example:

Submitting the form without providing any information will result in the following error:

Submitting with the name but invalid email address format will result in the following error:

Let's see how it works:

Then copy and paste the CSS code below in the CSS area:

Then code the JavaScript below:

All concepts in the code are similar to what we already learned (getting an element by ID, event listener, functions, etc.)
But the only item that is new is the "if statements".
Basically we are checking if the input field value ("content" is empty when the user hits submit, and if it is empty, we add the error message).
And we do the same for the email input field.

Lesson 7: JS Data Validation