js中的Math，他用于完成一般的数学作业。
还是先给出几个例子，希望大家能够多加指正我的错误
1，怎么用round()
<html> <body> <script type="text/javascript"> document.write(Math.round(0.60) + "<br />") document.write(Math.round(0.50) + "<br />") document.write(Math.round(0.49) + "<br />") document.write(Math.round(-4.40) + "<br />") document.write(Math.round(-4.60)) </script> </body> </html>
大家可以去运行一下，结果是：
1
1
0
-4
-5
２怎么用random()来返回一个0和１之间的随机数
<html> <body> <script type="text/javascript"> document.write(Math.random()) </script> </body> </html>
大家自己去测试一下结果
３，大家用max()来返回比较数中的最大的数
<html> <body> <script type="text/javascript"> document.write(Math.max(5,7) + "<br />") document.write(Math.max(-3,5) + "<br />") document.write(Math.max(-3,-5) + "<br />") document.write(Math.max(7.25,7.30)) </script> </body> </html>
结果是：
7
5
-3
7.3
４，大家用min()来返回比较数中最小的一个
<html> <body> <script type="text/javascript"> document.write(Math.min(5,7) + "<br />") document.write(Math.min(-3,5) + "<br />") document.write(Math.min(-3,-5) + "<br />") document.write(Math.min(7.25,7.30)) </script> </body> </html>
结果是：
5
-3
-5
7.25
下面是这个对象中所有的方法和属性
Math Object Methods
FF: Firefox, N: Netscape, IE: Internet Explorer
| Method | Description | FF | N | IE |
|---|---|---|---|---|
| abs(x) | Returns the absolute value of a number | 1 | 2 | 3 |
| acos(x) | Returns the arccosine of a number | 1 | 2 | 3 |
| asin(x) | Returns the arcsine of a number | 1 | 2 | 3 |
| atan(x) | Returns the arctangent of x as a numeric value between -PI/2 and PI/2 radians | 1 | 2 | 3 |
| atan2(y,x) | Returns the angle theta of an (x,y) point as a numeric value between -PI and PI radians | 1 | 2 | 3 |
| ceil(x) | Returns the value of a number rounded upwards to the nearest integer | 1 | 2 | 3 |
| cos(x) | Returns the cosine of a number | 1 | 2 | 3 |
| exp(x) | Returns the value of Ex | 1 | 2 | 3 |
| floor(x) | Returns the value of a number rounded downwards to the nearest integer | 1 | 2 | 3 |
| log(x) | Returns the natural logarithm (base E) of a number | 1 | 2 | 3 |
| max(x,y) | Returns the number with the highest value of x and y | 1 | 2 | 3 |
| min(x,y) | Returns the number with the lowest value of x and y | 1 | 2 | 3 |
| pow(x,y) | Returns the value of x to the power of y | 1 | 2 | 3 |
| random() | Returns a random number between 0 and 1 | 1 | 2 | 3 |
| round(x) | Rounds a number to the nearest integer | 1 | 2 | 3 |
| sin(x) | Returns the sine of a number | 1 | 2 | 3 |
| sqrt(x) | Returns the square root of a number | 1 | 2 | 3 |
| tan(x) | Returns the tangent of an angle | 1 | 2 | 3 |
| toSource() | Represents the source code of an object | 1 | 4 | - |
| valueOf() | Returns the primitive value of a Math object | 1 | 2 | 4 |
Math Object Properties
| Property | Description | FF | N | IE |
|---|---|---|---|---|
| constructor | A reference to the function that created the object | 1 | 2 | 4 |
| E | Returns Euler's constant (approx. 2.718) | 1 | 2 | 3 |
| LN2 | Returns the natural logarithm of 2 (approx. 0.693) | 1 | 2 | 3 |
| LN10 | Returns the natural logarithm of 10 (approx. 2.302) | 1 | 2 | 3 |
| LOG2E | Returns the base-2 logarithm of E (approx. 1.414) | 1 | 2 | 3 |
| LOG10E | Returns the base-10 logarithm of E (approx. 0.434) | 1 | 2 | 3 |
| PI | Returns PI (approx. 3.14159) | 1 | 2 | 3 |
| prototype | Allows you to add properties and methods to the object | 1 | 2 | 4 |
| SQRT1_2 | Returns the square root of 1/2 (approx. 0.707) | 1 | 2 | 3 |
| SQRT2 | Returns the square root of 2 (approx. 1.414) | 1 | 2 | 3 |
