<!DOCTYPE html>charset="utf-8"W3Cschool教程(w3cschool.cn)id="demo"单击按钮显示不同数值的平方根。onclick="myFunction()"点我function myFunction(){var a=Math.sqrt(0);var b=Math.sqrt(1);var c=Math.sqrt(9);var d=Math.sqrt(64);var e=Math.sqrt(-9);var x=document.getElementById("demo")x.innerHTML=a + "<br>" + b + "<br>" + c + "<br>" + d + "<br>" + e;}