Essentials of Javascript - Cultural View

JavaScript syntax 19
Comments
Comment syntax is the same as in C++ and many other languages.
// a short, one-line comment
/* this is a long, multi-line comment
about my script. May it one day
be great. */
Note that JavaScript explicitly forbids nesting of comments, e.g.
/* You can't do
*/
/* this */
/* But you can
//Do this.
*/
// And you can /* also do this */
// As /* well /* as this */ */
Variables
Variables in standard JavaScript have no type attached, and any value can be stored in any variable. Variables can be
declared with a var statement. These variables are lexically scoped and once a variable is declared, it may be
accessed anywhere inside the function where it is declared. Variables declared outside any function, and variables
first used within functions without being declared with 'var', are global. Here is an example of variable declarations
and global values:
x = 0; // A global variable
var y = 'Hello!'; // Another global variable
function f(){
}
var z = 'foxes'; // A local variable
twenty = 20; // Global because keyword var is not used
return x; // We can use x here because it is global
// The value of z is no longer available