JavaScript VARIABLES AND DATA TYPES

OUTPUT WITHOUT ALERT OR FORM CONSOLE.LOG();

Holding information

example A = B + C; Cubby Hole 2: add this value Cubby Hole 1: take this value Cubby Hole 3: place it here

Defining CUBBY HOLES  They are called variables  Define them  Give them values  Take values from them

= means “takes the value of” A takes the value of B+C

VALUES

What values can it take?  Any “expression”  What is an expression?  Variables  Constants  Operators  functions  Different for numbers and strings

Numbers  Regular math operators  Variables  Constants  Functions (random, floor)

Strings  Think of Scrabble tiles  Each tile is a  Letter  Number  Punctuation mark  Space (blank)

What is a String?  A literal string must be inside double quotes or single quotes  “this is a string” and this is not a string.  Remember to beware cut and paste

Concatenating (formally)  It means combining two or more things into one thing  + Anything can be concatenated  “awe” & “some” = “awesome”  Whitespace only matters inside quotes  “a”+“b” same as “a” = “b”  “a ” + “b” NOT the same as “a” + “b”

Substring  A substring is also a String  A substring is a part of another string  “cake” is a substring of “birthday cake”  so are “day”, “thd”, and “y cake”  “they” is not, neither is “hello” or “dude”  Will come back to how to extract substrings

Referencing characters Each character has a position Note that it starts at 0, not 1 HIMOM