Some random projections from Week 3, 8-29-06

*  "legal" characters for identifiers (variable names, function
   names, names you choose for things)

   *   1st letter: letter, underscore, or a dollar sign $

       (although considered poor style to use a $ as first char,
       because code generation tools tend to use that)

   *   subsequent characters: any letter, digit, underscore, or $

   *   identifiers cannot be the same as JavaScript keywords

*  now, strings --- they can contain all sorts of characters...
   (a value written in double-quotes)

   var name = "^$%%&#&^*UI%T*OT"
   
   *   what if you want a " in a string? 
       "\"What's up, Doc?\", said Bugs Bunny"

   *   \ can be used to get "special" characters

   *   "\n" for a newline, "\t" for a tab

   *   "\\" will get you a backslash character

*  a few useful JavaScript functions and operators for
   converting between types..

   *   JavaScript has:
       *   3 primitive data types (number, string, and Boolean)
       *   1 composite type (Object)
       *   4 special values: null, undefined, NaN, Infinity

   *   Number(str) - that will try to convert str to a number
       (it will return NaN if it can't)
       parseInt(str) - will try to convert it to an integer
       parseFloat(str) - will try to convert it to a floating
                         point value

   *   String(thing) - will return string version of thing

   *   typeof(thing) - returns a string saying what kind of thing 
                       it is

(added after class!)
   *   isNaN(thing) - returns true if thing is the special value NaN