​x
 
<!DOCTYPE html>
<html>
<body>
​
<h1>JavaScript 数学</h1>
​
<p>Math.abs() 返回数的绝对值：</p>
​
<p id="demo"></p>
​
<script>
let a = Math.abs(7.25);
let b = Math.abs(-7.25);
let c = Math.abs(null);
let d = Math.abs("Hello");
let e = Math.abs(2-3);
document.getElementById("demo").innerHTML = 
a + "<br>" + b + "<br>" + c + "<br>" + d + "<br>" + e;
</script>
​
</body>
</html>
​