First, a quick word about variables. A value is an indentifier that
-are not typed. In other words, we can to any variable can hold any
-value. Most dynamic language (such as Perl, Python and Ruby) are like
+are not typed. In other words, any variable can hold any value. Most
+dynamic language (such as Perl, Python and Ruby) are like this.
Always declare variables with a var statement, because sometimes a
missing var can cause a hard-to-find bug. Experiments at the command
line are the only exception to this rule.
+We can change an array or a 'dictionary'. Immutable values are values
+that can't be changed. We can't change, for example, the third
-Strings and numbers are the simple
+Strings literals are delimited by single or double quote marks, with
+special characters escaped. There's no difference between the two
+forms (except in single quote you don't have to escape double quote,
+and vice versa.) Generally, I prefer the single quote form as it's
+less busy on the eye and slightly easier to type.
+why, and which to use when. For now we'll simply note that they are
+different, because their types are different.
+ js> s.lang === undefined