Javascript is a typeless, interpreted language
Case-sensitive
HTML is not case-sensitive
Ignore spaces, tabs, and newlines (except keywords, variables, and regular expressions)
";"Semicolon is optional
//Single-line comment
/*Multi-line comment*/
The identifier must start with a letter, underscore, and $ symbol
Keyword: break delete function return typeof
case do if switch var
catch else in this void
continue false instanceof throw while
debugger finally new true with
default for null try
function(function), It is an object of executable code
Ordered collection<=>Set
boolean isNaN(numValue) ///numValue returns false if it is meaningful, and true if it is meaningless
Escape character sequence escape character Instructions for use
1 b Backspace
2 f Form Feed
3 n New Line
4 r Carriage Return
5 t System Table (Tab)
6 ' Single quotation mark
7 " Double quotation mark
8 \ Backslash (Backslash)
Question: "