Numbers & Number Methods

Unlike Python, JavaScript only has one type of number. Numbers in JavaScript can be written with or without decimals, and you can use scientific notation.

var x = 10;

var x = 10.1;

var x = 12e5;

JavaScript numbers use 64 bits, with the number in bits 0-51, any exponents in bits 52 to 62, and the sign (+ or -) in bit 63.

Just as with strings, numbers have a variety of methods associated with them.

toString() converts a number to a string of characters.

var x = 10;

x.toString();

toExponential() converts a number to exponential notation. You can specify how many decimal places you want in the number part.

var x = 10.543;

x.toExponential(2);

x.toExponential(3);

toFixed() converts a number to a fixed number of decimal places.

var x = 10.543;

x.toFixed(0);

toPrecision() returns a string with a fixed length.

var x = 10.543;

x.toPrecision(2);

More info on number methods.