Wednesday, July 1, 2009

Java Script Built in functions

Numbers

3 or 7.987, Integer and floating-point numbers.

  • Integers can be positive, 0, or negative; Integers can be expressed in decimal (base 10), hexadecimal (base 16), and octal (base 8). A decimal integer literal consists of a sequence of digits without a leading 0 (zero). A leading 0 (zero) on an integer literal indicates it is in octal; a leading 0x (or 0X) indicates hexadecimal. Hexadecimal integers can include digits (0-9) and the letters a-f and A-F. Octal integers can include only the digits 0-7.
  • A floating-point number can contain either a decimal point, an "e" (uppercase or lowercase), which is used to represent "ten to the power of" in scientific notation, or both. The exponent part is an "e" or "E" followed by an integer, which can be signed (preceded by "+" or "-"). A floating-point literal must have at least one digit and either a decimal point or "e" (or "E").

Booleans

True or False. The possible Boolean values are true and false. These are special values, and are not usable as 1 and 0. In a comparison, any expression that evaluates to 0 is taken to be false, and any statement that evaluates to a number other than 0 is taken to be true.

Strings

"Hello World !" Strings are delineated by single or double quotation marks. (Use single quotes to type strings that contain quotation marks.)

Objects

myObj = new Object();

Null

Not the same as zero - no value at all. A null value is one that has no value and means nothing.

Undefined

A value that is undefined is a value held by a variable after it has been created, but before a value has been assigned to it.

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