Page 164 - DCAP408_WEB_PROGRAMMING

Web Programming

Notes 5.7.4 Math Object

The Math object allows you to perform mathematical tasks.
The Math object includes several mathematical constants and methods.
Syntax for using properties/methods of Math:
var pi_value=Math.PI;
var sqrt_value=Math.sqrt(16);
Note: Math is not a constructor. All properties and methods of Math can be called by using Math
as an object without creating it.
 Mathematical Constants
JavaScript provides eight mathematical constants that can be accessed from the Math
object. These are: E, PI, square root of 2, square root of 1/2, natural log of 2, natural log of
10, base-2 log of E, and base-10 log of E.
You may reference these constants from your JavaScript like this:
Math.E
Math.PI
Math.SQRT2
Math.SQRT1_2
Math.LN2
Math.LN10
Math.LOG2E

Math.LOG10E
 Mathematical Methods
In addition to the mathematical constants that can be accessed from the Math object there
are also several methods available.
The following example uses the round() method of the Math object to round a number to
the nearest integer:
document.write(Math.round(4.7));
The code above will result in the following output:
5
The following example uses the random() method of the Math object to return a random
number between 0 and 1:
 Document.write(Math.random());
The code above can result in the following output:
011917396456824547
The following example uses the floor() and random() methods of the Math object to return
a random number between 0 and 10:
document.write(Math.floor(Math.random()*11));
The code above can result in the following output:
7

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