1. The common usage of Math
Math.random () // 0-1 random number
Math.round () // rounded to integer
Math.ceil () // rounded up
Math.floor () // rounded down
Math.abs () // absolute value
Math.max (num1, num2 ....) // compare the maximum value
Math.min (num1, num2 ....) // compare the minimum
Math.PI // p 3.1415926 - 3.1415927
Math.pow (x, y) // x power of y
Math.sqrt () // square root
Math.sin
Math.cos
Math.tan
Note:
Used to represent the angle in radians
eg: b = c * sin (x); // x represents a degree. Represents the angle (2 * Math.PI / 360) * x in radians;
2. Case
a. Make a hexagon
Bridesmaid sh = 150 / Mathktn ((2 * Mathkpi / 360) * 30);
for (var i = 0; i < 6; i++) {
box.innerHTML += '<div style="transform-origin: center center '+(-z)+'px;transform: translateZ('+z+'px) rotateY('+(i*60)+'deg);background:'+randomColor()+';"></div>';
}
// random color (color value in hexadecimal notation.)
function randomColor() {
var str = "0123456789abcdef"
var color = '#';
for (var i = 0; i < 6; i++) {
// each time a random subscript 0-15
color += str.charAt((Math.random() * 15));
}
return color;
}
</script>
effect:
b. parabola Case
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
* {
margin: 0;
padding: 0
}
div:nth-of-type(1) {
width: 600px;
height: 2px;
background: red;
position: absolute;
top: 300px;
}
div:nth-of-type(2) {
width: 2px;
height: 600px;
background: blue;
position: absolute;
left: 300px;
}
span {
display: block;
width: 2px;
height: 2px;
position: absolute;
border-radius: 1px;
background: red;
}
</style>
</head>
<body>
<div></div>
<div></div>
<script>
for(var x= -300; x<=300;x++) {
var y = 0.01 * Math.pow (x, 2);
document.write('<span style="left:' +(x+300)+ 'px;top:' +(y+300)+'px;"></span>');
}
</script>
</body>
</html>
display effect:
