What is JavaScript ?
JavaScript is the
set of rules. Those rules
that define a correctly structured JavaScript program.
Why do we need JavaScript ?
JavaScript is
mainly used for client-side scripting within Web browsers.
How do we write code
in JavaScript ?
JavaScript is
case sensitive. While scriptinf we should start the name of a constructor with a capitalised
letter, and the name of a function or variable with a lower-case letter.
Spaces, tabs and
newlines used outside of string constants are called whitespace.
Comment syntax matches
to C++ and some other languages.
// This is
as one-line comment
/* this is a
long, multi-line comment
For which the syntax is different */
/* You
should not /* nest the comments */ Syntax error */
Variables in JavaScript
There is no "type" attached to Variables in JavaScript. Any value can be stored in any variable.
having said that , Variables are declared with a var statement, multiple variables can be
declared at once.
An identifier must start with a letter,
underscore (_), or dollar sign ($); subsequent characters can also be digits
(0-9). Because JavaScript is case sensitive, letters include the characters
"A" through "Z" (uppercase) and the characters
"a" through "z" (lowercase).