var diff=0.00000000001//精度<br>
var GetSqrt= function(n){ <br>
var s = n / 2//假设的平方根初值 <br>
while (NotFit(s,n)) { <br>
s = ((n / s) + s) / 2<br>
} <br>
return s<br>
},NotFit=function( num, n){ <br>
var r= num*num<br>
var d = Abs(n - Abs(r))<br>
if(d>diff){ <br>
return true<br>
}<br>
return false<br>
},Abs=function(a){<br>
if(a>=0 )return a<br>
else return -a<br>
}<br><br>
return {<br>
sqrt:GetSqrt,<br>
abs:Abs<br>
}<br>})()<br><br>//sqrt<br>alert(MyMath.sqrt(0))//0<br>alert(MyMath.sqrt(1))//1<br>alert(MyMath.sqrt(9))//3<br><br>//abs<br>alert(MyMath.abs(-4))//4上面的代码自己测试可以运行
<%@ page language="java" import="java.util.*" pageEncoding="gb2312"%><%
String path = request.getContextPath()
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<script type="text/javascript">
function getById(id){
return document.getElementById(id)
}
function getInfo(){
var num=getById("num").value
if(isNaN(num) || num<1){
alert("请输入正整数！")
}else{
alert(num+"的平方值为："+num*num)
alert(num+"的平方根为："+Math.sqrt(num))
}
}
</script>
</head>
<body>
<input type="text" size="20" id="num"><input type="button" value="计算" onclick="getInfo()">
</body>
</html>
楼主，望采纳啊，^_^，给点评价哦 ,可以结贴了。绝对没问题
JS中可以通过sqrt获得数字的平方根JS中我们可以通过sqrt()函数获得数字的平方根.语法如下：
Math.sqrt(x)
下面来看一些sqrt()实例：
<script language='JavaScript' type='text/JavaScript'>
<!--
document.write(Math.sqrt(4))// output is 2
document.write("<br>")
document.write(Math.sqrt(64))// output is 8
document.write("<br>")
document.write(Math.sqrt(9))// output is 3
document.write("<br>")
document.write(Math.sqrt(27))// output is 5.196152422706632
document.write("<br>")
document.write(Math.sqrt(0.36))// output is 0.6
document.write("<br>------------<br>")
document.write(Math.sqrt(-64))// output is Nan
document.write("<br>")
document.write(Math.sqrt(-9))// output is NaN
//-->
</script>
