Numbers
JavaScript uses 64 bits to store number values
Fractional numbers
Scientific notation
Special Numbers
Infinity
Infinity and -Infinity represent positive and negative infinities
NaN
Not a number. The returned result if you try to do mathematical nonsense
Boolean
Strings can also be compared
Uppercase characters are always less than lower case characters, so “Z” < “a”. Non alphabetic characters are less than alphabetic characters
Empty values
There are two special empty values, null & undefined that denote the absence of any meaningful value. They can be used interchangeably and are an accident of JavaScripts design.