Chapter 2

Understanding Variables


Bullet Getting your head around variables

Bullet Assigning names to variables

Bullet Introducing JavaScript data types

Bullet Figuring out numbers

Bullet Stringing strings together

You should imagine variables as tentacles, rather than boxes. They do not contain values; they grasp them.


You may have heard about — or perhaps even know — someone who, through mishap or misfortune, has lost the ability to retain short-term memories. If you introduce yourself to one of these folks, they’ll be asking you your name again five minutes later. They live in a perpetual present, seeing the world anew every minute of every day.

What, I’m sure you’re asking yourself by now, can any of this possibly have to do with coding? Just that, by default, your JavaScript programs also live a life without short-term memory. The web browser executes your code one statement at a time, until no more statements are left to process. It all happens in the perpetual present. Ah, ...

Get Web Coding & Development All-in-One For Dummies, 2nd Edition now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.