Math object in JavaScript
Math mathematical object
The Math object is a static object. In other words: when using the Math object, there is no need to create an instance.
Math.PI: Pi.
Math.abs(): Absolute value. For example: Math.abs(-9) = 9
Math.ceil(): round up (add 1 to the integer and remove the decimal). For example: Math.ceil(10.2) = 11
Math.floor(): Round down (remove decimals directly). For example: Math.floor(9.888) = 9
Math.round(): Rounding. For example: Math.round(4.5) = 5; Math.round(4.1) = 4
Math.pow(x,y): Find the yth power of x. For example: Math.pow(2,3) = 8
Math.sqrt(): Find the square root. For example: Math.sqrt(121) = 11
Math.random(): Returns a random decimal between 0 and 1. For example: Math.random() = 0.12204467732259783
Note: Find a random number between (min, max). The formula is: Math.random()*(max-min)+min
Example: Random integer between 0-10; find random number between 10-20 Integer; Find a random integer between 20 and 30; Find a random integer between 7 and 91
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>php.cn</title>
<script>
//求兩個整數(shù)之間的隨機整數(shù)
//定義隨機數(shù)的函數(shù)
function getRandom(min,max){
//求隨機數(shù)
var random =Math.random()*(max-min)+min;
//向下取整
random = Math.floor(random);
//輸出結果
document.write(random+"<hr>");
}
//調(diào)用函數(shù)
getRandom(0,100);
getRandom(5,89);
getRandom(100,999);
</script>
</head>
<body>
</body>
</html>Example: Random web page background color
<!DOCTYPE HTML> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>php.cn</title> </head> <body> </body> </html> <script> var min = 100000; var max = 999999; var random = Math.random() *(max-min)+min; //向下取整 random = Math.floor(random); document.body.bgColor = "#"+random; </script>
