代码示例:(标识:jsck_toexponential_2)
<!DOCTYPE html>
<html>
<body>

<h2>JavaScript 数字</h2>

<p>toExponential() 方法将数字转换为指数计数法:</p>

<p id="demo"></p>

<script>
let num = 5.56789;
let n = num.toExponential(3);
document.getElementById("demo").innerHTML = n;
</script>

</body>
</html>
运行结果: