JavaScript Math object
JavaScript Math (arithmetic) object
The function of the Math (arithmetic) object is to perform common arithmetic tasks.
How to use round():
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文网(php.cn)</title>
</head>
<body>
<p id="demo">单击按钮舍入与“9.5”最接近的整数</p>
<button onclick="myFunction()">点我</button>
<script>
function myFunction(){
document.getElementById("demo").innerHTML=Math.round(9.5);
}
</script>
</body>
</html>How to use random() to return a random number between 0 and 1:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文网(php.cn)</title>
</head>
<body>
<p id="demo">点击按钮显示一个随机数</p>
<button onclick="myFunction()">点我</button>
<script>
function myFunction(){
document.getElementById("demo").innerHTML=Math.random();
}
</script>
</body>
</html>How to use max() to return two The larger of the given numbers. (Prior to ECMASCript v3, this method had only two parameters.):
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文网(php.cn)</title>
</head>
<body>
<p id="demo">单击按钮返回5到10之间的最大值。</p>
<button onclick="myFunction()">点我</button>
<script>
function myFunction(){
document.getElementById("demo").innerHTML=Math.max(5,10);
}
</script>
</body>
</html>How to use min() to return the smaller of two given numbers. (Prior to ECMASCript v3, this method had only two parameters.)
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文网(php.cn)</title>
</head>
<body>
<p id="demo">单击按钮返回5到10之间最小的值。</p>
<button onclick="myFunction()">点我</button>
<script>
function myFunction(){
document.getElementById("demo").innerHTML=Math.min(5,10);
}
</script>
</body>
</html>Math object
The purpose of the Math (arithmetic) object is to perform common arithmetic tasks.
The Math object provides a variety of arithmetic value types and functions. There is no need to define this object before using it.
Syntax for using Math properties/methods:
var x=Math.PI;
var y=Math.sqrt(16);
Note: Math The object does not need to be defined before using it.
Arithmetic values
JavaScript provides 8 arithmetic values that can be accessed by the Math object:
You can refer to the following methods of using Javascript constants:
Math. E
Math.PI
Math.SQRT2
Math.SQRT1_2
Math.LN2
Math.LN10
Math.LOG2E
Math.LOG10E
Arithmetic methods
In addition to the arithmetic values that can be accessed by the Math object, there are several functions (methods) that can be used.
The following example uses the round method of the Math object to round a number.
document.write(Math.round(4.7));
The output of the above code is:
5
The following example uses the Math object The random() method returns a random number between 0 and 1:
document.write(Math.random());
The output of the above code is:
0.18346685613505542
The following example uses the floor() method and random() of the Math object to return a random number between 0 and 11:
document.write (Math.floor(Math.random()*11));
The output of the above code is:
9
