JavaScript Basic Learning-javascript authoritative guide--3.1 numbers

Digital

JavaScript does not distinguish between integers and floating-point numbers, all of which are floating-point number.

The opposite number is obtained by adding the minus sign before the number.

3.1.1 Plastic Direct Volume

Hex: 0X or 0x

Do not mark: decimal

Octal: 0

Note: A write JavaScript supports octal.

3.1.2 Floating-point Direct volume

1.2E-3 = 1.2 * 10 Negative 3 times

3.1.3 Arithmetic operations

Overflow: The result of the operation is more than the result of the number can be expressed, overflow and underflow.

Underflow: The result of the operation is infinitely close to 0.

0 do divisor: The result is infinity or negative infinity.

0/0	NaN
Infinity/Infinity	NaN
Negative root	NaN
is not a number or an operation that cannot be converted into a number	NaN

Positive 0 and minus 0, except to do the divisor result is not the same, the others are the same

3.1.4 Binary floating-point numbers and rounding

Binary floating-point notation cannot accurately represent 0.1 of such numbers.

3.1.5 Date and time

var New Date (2012,12,1); var New  var elp = now- then;console.log (ELP);//82671145445 interval of milliseconds 

varNew Date (2011,12,3,12,23,56);
Console.log (that.getfullyear); Console.log (That.getmonth); Console.log (That.getdate ()); Console.log (That.getday () ); Console.log (That.gethours ()); Console.log (getUTCHours ());//Do not know why 360 does not have this, referenceerror:getutchours is not Defined

JavaScript Basic Learning-javascript authoritative guide--3.1 numbers