The JavaScript Diaries: Part 14/Page 2
[previous] [next]
The JavaScript Diaries: Part 14  The Math Object
Methods
Name  Description 
abs()  Returns the absolute value of a number 
acos()  Returns the arccosine (in radians) of a number 
asin()  Returns the arcsine (in radians) of a number 
atan()  Returns the arctangent (in radians) of a number 
atan2()  Returns the arctangent of the quotient of its arguments 
ceil()  Returns the smallest integer greater than or equal to a number 
cos()  Returns the cosine of a number 
exp()  Returns Enumber, where number is the argument, and E is Euler's constant, the base of the natural logarithms 
floor()  Returns the largest integer less than or equal to a number 
log()  Returns the natural logarithm (base E) of a number 
max()  Returns the greater of two numbers 
min()  Returns the lesser of two numbers 
pow()  Returns base to the exponent power, that is, base exponent 
random()  Returns a pseudorandom number between 0 and 1 
round()  Returns the value of a number rounded to the nearest integer 
sin()  Returns the sine of a number 
sqrt()  Returns the square root of a number 
tan()  Returns the tangent of a number 
Usage in Scripts
Let's see what we can do with some of these methods. (By now you can probably figure out these scripts without an explanation, so I won't go into greater detail. Instead, we'll focus on the methods themselves. Still, if a script begins to become complex, I'll stop and explain it. If you need further help, you can always email me.)
Finding the Square Root
An obvious use is to find the square root of a number. Here's a basic script for doing the calculation:
This then would be called by the following, placed in the body
of the document:
Rounding Numbers
Another calculation we could perform would be to round off a number. This script uses the code we wrote previously to find the circumfrence of a circle.
You could also use the round()
method to set the number of decimal places:
The formula for rounding a number to x
decimal points is:

Keep in mind that the format is as follows:

[previous] [next]
URL: