​x
 
<!DOCTYPE html>
<html>
<body>
​
<h1>JavaScript 数字</h1>
​
<h2>Number.isFinite() 方法</h2>
​
<p>如果值是有限的合法数字，则 Number.isFinite() 返回 true：</p>
​
<p id="demo"></p>
​
<p>Internet Explorer 11（或更早版本）不支持 Number.isFinite()。</p>
​
<script>
let res = "";
res += Number.isFinite(5-2) + ": 5-2<br>";
res += Number.isFinite(5/2) + ": 5/2<br>";
res += Number.isFinite(0) + ": 0<br>";
res += Number.isFinite(0/0) + ": 0/0<br>";
res += Number.isFinite(Infinity) + ": Infinity<br>";
res += Number.isFinite(-Infinity) + ": -Infinity<br>";
res += Number.isFinite(NaN) + ": NaN<br>";
​
document.getElementById("demo").innerHTML = res;
</script>
​
</body>
</html>
​