HTML and CSS Reference
guage; that is, the kinds of data that can be stored and manipulated within a program,
such as strings and numbers. To proceed to the next chapters, you should know:
1. What is meant by primitive data types.
2. What numeric literals are.
3. How to concatenate strings.
4. The two values for a Boolean.
5. What the typeof operator returns.
6. What is meant by null , undefined .
7. The difference between a variable and a constant.
8. The difference between loosely typed and strongly typed languages.
9. What scope is.
10. What types can be assigned to a variable.
11. How to name a variable.
12. When var is used.