Using undeclared variables - Programming in HTML5 Exam 70-480 Training Course - Part 3 | web Developer courses

Duration: 15:36 min

Summary: Today, we will continue our discussion with variables. We will see what happens when we use undeclared variables. Also, we will experiment with a very important concept: The difference between null and undefined. We will also see how to work with conditionals and Boolean type. At the end, we will explore the === operator. We will see that when using the == operator, JavaScript uses type coercion. In order to write safe code, use the === operator because it not only compare the content of the variables, but also their types.