本文目录一览：
- 1、用JS脚本实现网页计算器！！求代码！求高手！！！！
- 2、用JavaScript做个网页版的计算器？
- 3、如何用JS创建一个简单的网页计算器
- 4、怎么在网页上制作一个简易计算器
- 5、用JS做一个简单的网页计算器如图所示，只进行简单的加减乘除运算
用JS脚本实现网页计算器！！求代码！求高手！！！！
C#的要不。。。
C#软件中也能做js
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication2
{
public partial class 计算机 : Form
{
double Num1 = 0;//这三行是考虑计算时候要用的
double Num2 = 0;//这三行是考虑计算时候要用的
string op = "";//这三行是考虑计算时候要用的
public 计算机()
{
InitializeComponent();
}
private void btnNum1_Click(object sender, EventArgs e)
{
if (txtResult.Text != "")
{
double temp = double.Parse(txtResult.Text);//这个是做开平方的。。。
temp = Math.Sqrt(temp);
txtResult.Text = temp.ToString();
}
}
private void button6_Click(object sender, EventArgs e)
{
if (txtResult.Text != "")
{
double temp = double.Parse(txtResult.Text);//这个是那个“阶乘键的”用的是“！”标记。
double factor = 1;
for (int i = 1; i = temp; i++)
factor = factor * i;
txtResult.Text = factor.ToString();
}
}
private void btnNum1_Click_1(object sender, EventArgs e)
{
Button btn = sender as Button;//这个是第一步：要在计算器中输入数字的。。。
txtResult.Text += btn.Text;
}
private void btnNum3_Click(object sender, EventArgs e)
{
if (txtResult.Text != "")
{
double temp = double.Parse(txtResult.Text);//这个是那个“正弦函数”。。
temp = Math.Sin(temp);
txtResult.Text = temp.ToString();
}
}
private void btnPoint_Click(object sender, EventArgs e)
{
if (txtResult.Text == "")
{
txtResult.Text = "0.";//这个是“小数点”问题。。。要考虑到：1、一串数字中不能出现两个小数点。。2.第一个输入小数点时问题
}
else
{
if (txtResult.Text.IndexOf(".") == -1)
{
txtResult.Text += ".";
}
}
}
private void btnNum0_Click(object sender, EventArgs e)
{
Button btn = sender as Button;//这是数字“0”的问题。。首先不能第一个为0.。。
if (txtResult.Text == "0")
{
txtResult.Text = btn.Text;
}
else
{
txtResult.Text += btn.Text;
}
}
private void btnAdd_Click(object sender, EventArgs e)
{
Button btn = sender as Button;//这是解决当第一个按“+”号时程序出错的状况。。。
if (txtResult.Text != "")
Num1 = double.Parse(txtResult.Text);
op = btn.Text;
txtResult.Text = "";
}
private void btnCalculate_Click(object sender, EventArgs e)
{
double result = 0;
Num2 = double.Parse(txtResult.Text);/////这是处理“=”的问题。。。不过还有些不足。。
switch (op)
{
case "+": result = Num1 + Num2; break;
case "-": result = Num1 - Num2; break;
case "*": result = Num1 * Num2; break;
case "/": result = Num1 / Num2; break;
default: result = 0; break;
}
txtResult.Text = result.ToString();
}
private void btnClear_Click(object sender, EventArgs e)
{
txtResult.Text = "";///////////////这是处理”清除键“的功能。。即:清除所有数字。。
Num1 = 0;
Num2 = 0;
op = "";
}
private void btnBackspace_Click(object sender, EventArgs e)
{
int len = txtResult.Text.Length;
if (len != 0)
txtResult.Text = txtResult.Text.Substring(0, len - 1);////这是处理“退格键”的问题。。即：除去最后一个数字。。。
}
private void button20_Click(object sender, EventArgs e)
{
if (txtResult.Text != "")
{
double temp = double.Parse(txtResult.Text);////这是处理“相反数”的问题。。即：先按个‘9“键。再按此键变为”-9“
temp = temp * (-1);
txtResult.Text = temp.ToString();
}
}
private void button4_Click(object sender, EventArgs e)
{
if (txtResult.Text != "")
{
double temp = double.Parse(txtResult.Text);//这是”余弦“问题。。。
temp = Math.Cos(temp);
txtResult.Text = temp.ToString();
}
}
private void button4_Click_1(object sender, EventArgs e)
{
if (txtResult.Text != "")
{
double temp = double.Parse(txtResult.Text);//////这是处理”正切“问题。。
temp = Math.Tan(temp);
txtResult.Text = temp.ToString();
}
}
}
}
用JavaScript做个网页版的计算器？
哎呀！这个简单！！我给你啦！！！下面就是用Jscript写的计算器了复制后保存一切就OK的啦！！！！！！！！！
html
head
meta http-equiv="Content-Type" content="text/html; charset=gb2312"
!--written by GoldHuman li hai--
!--2000.8--
title科学计算器/title
style
!--
BODY {
font-family: "宋体", "Arial", "Times New Roman";
font-size: 9pt;
background-color: #edf0e1;
color: #0001fC;
background-attachment: fixed;
}
td{font-family: "宋体", "Arial Narrow", "Times New Roman"; font-size:9pt; font-color:#000000}
//--
/style
script language="javascript"
!--
var endNumber=true
var mem=0
var carry=10
var hexnum="0123456789abcdef"
var angle="d"
var stack=""
var level="0"
var layer=0
//数字键
function inputkey(key)
{
var index=key.charCodeAt(0);
if ((carry==2 (index==48 || index==49))
|| (carry==8 index=48 index=55)
|| (carry==10 (index=48 index=57 || index==46))
|| (carry==16 ((index=48 index=57) || (index=97 index=102))))
if(endNumber)
{
endNumber=false
document.calc.display.value = key
}
else if(document.calc.display.value == null || document.calc.display.value == "0")
document.calc.display.value = key
else
document.calc.display.value += key
}
function changeSign()
{
if (document.calc.display.value!="0")
if(document.calc.display.value.substr(0,1) == "-")
document.calc.display.value = document.calc.display.value.substr(1)
else
document.calc.display.value = "-" + document.calc.display.value
}
//函数键
function inputfunction(fun,shiftfun)
{
endNumber=true
if (document.calc.shiftf.checked)
document.calc.display.value=decto(funcalc(shiftfun,(todec(document.calc.display.value,carry))),carry)
else
document.calc.display.value=decto(funcalc(fun,(todec(document.calc.display.value,carry))),carry)
document.calc.shiftf.checked=false
document.calc.hypf.checked=false
inputshift()
}
function inputtrig(trig,arctrig,hyp,archyp)
{
if (document.calc.hypf.checked)
inputfunction(hyp,archyp)
else
inputfunction(trig,arctrig)
}
//运算符
function operation(join,newlevel)
{
endNumber=true
var temp=stack.substr(stack.lastIndexOf("(")+1)+document.calc.display.value
while (newlevel!=0 (newlevel=(level.charAt(level.length-1))))
{
temp=parse(temp)
level=level.slice(0,-1)
}
if (temp.match(/^(.*\d[\+\-\*\/\%\^\\|x])?([+-]?[0-9a-f\.]+)$/))
document.calc.display.value=RegExp.$2
stack=stack.substr(0,stack.lastIndexOf("(")+1)+temp+join
document.calc.operator.value=" "+join+" "
level=level+newlevel
}
//括号
function addbracket()
{
endNumber=true
document.calc.display.value=0
stack=stack+"("
document.calc.operator.value=" "
level=level+0
layer+=1
document.calc.bracket.value="(="+layer
}
function disbracket()
{
endNumber=true
var temp=stack.substr(stack.lastIndexOf("(")+1)+document.calc.display.value
while ((level.charAt(level.length-1))0)
{
temp=parse(temp)
level=level.slice(0,-1)
}
document.calc.display.value=temp
stack=stack.substr(0,stack.lastIndexOf("("))
document.calc.operator.value=" "
level=level.slice(0,-1)
layer-=1
if (layer0)
document.calc.bracket.value="(="+layer
else
document.calc.bracket.value=""
}
//等号
function result()
{
endNumber=true
while (layer0)
disbracket()
var temp=stack+document.calc.display.value
while ((level.charAt(level.length-1))0)
{
temp=parse(temp)
level=level.slice(0,-1)
}
document.calc.display.value=temp
document.calc.bracket.value=""
document.calc.operator.value=""
stack=""
level="0"
}
//修改键
function backspace()
{
if (!endNumber)
{
if(document.calc.display.value.length1)
document.calc.display.value=document.calc.display.value.substring(0,document.calc.display.value.length - 1)
else
document.calc.display.value=0
}
}
function clearall()
{
document.calc.display.value=0
endNumber=true
stack=""
level="0"
layer=""
document.calc.operator.value=""
document.calc.bracket.value=""
}
//转换键
function inputChangCarry(newcarry)
{
endNumber=true
document.calc.display.value=(decto(todec(document.calc.display.value,carry),newcarry))
carry=newcarry
document.calc.sin.disabled=(carry!=10)
document.calc.cos.disabled=(carry!=10)
document.calc.tan.disabled=(carry!=10)
document.calc.bt.disabled=(carry!=10)
document.calc.pi.disabled=(carry!=10)
document.calc.e.disabled=(carry!=10)
document.calc.kp.disabled=(carry!=10)
document.calc.k2.disabled=(carry=2)
document.calc.k3.disabled=(carry=2)
document.calc.k4.disabled=(carry=2)
document.calc.k5.disabled=(carry=2)
document.calc.k6.disabled=(carry=2)
document.calc.k7.disabled=(carry=2)
document.calc.k8.disabled=(carry=8)
document.calc.k9.disabled=(carry=8)
document.calc.ka.disabled=(carry=10)
document.calc.kb.disabled=(carry=10)
document.calc.kc.disabled=(carry=10)
document.calc.kd.disabled=(carry=10)
document.calc.ke.disabled=(carry=10)
document.calc.kf.disabled=(carry=10)
}
function inputChangAngle(angletype)
{
endNumber=true
angle=angletype
if (angle=="d")
document.calc.display.value=radiansToDegress(document.calc.display.value)
else
document.calc.display.value=degressToRadians(document.calc.display.value)
endNumber=true
}
function inputshift()
{
if (document.calc.shiftf.checked)
{
document.calc.bt.value="deg "
document.calc.ln.value="exp "
document.calc.log.value="expd"
if (document.calc.hypf.checked)
{
document.calc.sin.value="ahs "
document.calc.cos.value="ahc "
document.calc.tan.value="aht "
}
else
{
document.calc.sin.value="asin"
document.calc.cos.value="acos"
document.calc.tan.value="atan"
}
document.calc.sqr.value="x^.5"
document.calc.cube.value="x^.3"
document.calc.floor.value="小数"
}
else
{
document.calc.bt.value="d.ms"
document.calc.ln.value=" ln "
document.calc.log.value="log "
if (document.calc.hypf.checked)
{
document.calc.sin.value="hsin"
document.calc.cos.value="hcos"
document.calc.tan.value="htan"
}
else
{
document.calc.sin.value="sin "
document.calc.cos.value="cos "
document.calc.tan.value="tan "
}
document.calc.sqr.value="x^2 "
document.calc.cube.value="x^3 "
document.calc.floor.value="取整"
}
}
//存储器部分
function clearmemory()
{
mem=0
document.calc.memory.value=" "
}
function getmemory()
{
endNumber=true
document.calc.display.value=decto(mem,carry)
}
function putmemory()
{
endNumber=true
if (document.calc.display.value!=0)
{
mem=todec(document.calc.display.value,carry)
document.calc.memory.value=" M "
}
else
document.calc.memory.value=" "
}
function addmemory()
{
endNumber=true
mem=parseFloat(mem)+parseFloat(todec(document.calc.display.value,carry))
if (mem==0)
document.calc.memory.value=" "
else
document.calc.memory.value=" M "
}
function multimemory()
{
endNumber=true
mem=parseFloat(mem)*parseFloat(todec(document.calc.display.value,carry))
if (mem==0)
document.calc.memory.value=" "
else
document.calc.memory.value=" M "
}
//十进制转换
function todec(num,oldcarry)
{
if (oldcarry==10 || num==0) return(num)
var neg=(num.charAt(0)=="-")
if (neg) num=num.substr(1)
var newnum=0
for (var index=1;index=num.length;index++)
newnum=newnum*oldcarry+hexnum.indexOf(num.charAt(index-1))
if (neg)
newnum=-newnum
return(newnum)
}
function decto(num,newcarry)
{
var neg=(num0)
if (newcarry==10 || num==0) return(num)
num=""+Math.abs(num)
var newnum=""
while (num!=0)
{
newnum=hexnum.charAt(num%newcarry)+newnum
num=Math.floor(num/newcarry)
}
if (neg)
newnum="-"+newnum
return(newnum)
}
//表达式解析
function parse(string)
{
if (string.match(/^(.*\d[\+\-\*\/\%\^\\|x\])?([+-]?[0-9a-f\.]+)([\+\-\*\/\%\^\\|x\])([+-]?[0-9a-f\.]+)$/))
return(RegExp.$1+cypher(RegExp.$2,RegExp.$3,RegExp.$4))
else
return(string)
}
//数学运算和位运算
function cypher(left,join,right)
{
left=todec(left,carry)
right=todec(right,carry)
if (join=="+")
return(decto(parseFloat(left)+parseFloat(right),carry))
if (join=="-")
return(decto(left-right,carry))
if (join=="*")
return(decto(left*right,carry))
if (join=="/" right!=0)
return(decto(left/right,carry))
if (join=="%")
return(decto(left%right,carry))
if (join=="")
return(decto(leftright,carry))
if (join=="|")
return(decto(left|right,carry))
if (join=="^")
return(decto(Math.pow(left,right),carry))
if (join=="x")
return(decto(left^right,carry))
if (join=="")
return(decto(leftright,carry))
alert("除数不能为零")
return(left)
}
//函数计算
function funcalc(fun,num)
{
with(Math)
{
if (fun=="pi")
return(PI)
if (fun=="e")
return(E)
if (fun=="abs")
return(abs(num))
if (fun=="ceil")
return(ceil(num))
if (fun=="round")
return(round(num))
if (fun=="floor")
return(floor(num))
if (fun=="deci")
return(num-floor(num))
if (fun=="ln" num0)
return(log(num))
if (fun=="exp")
return(exp(num))
if (fun=="log" num0)
return(log(num)*LOG10E)
if (fun=="expdec")
return(pow(10,num))
if (fun=="cube")
return(num*num*num)
if (fun=="cubt")
return(pow(num,1/3))
if (fun=="sqr")
return(num*num)
if (fun=="sqrt" num=0)
return(sqrt(num))
if (fun=="!")
return(factorial(num))
if (fun=="recip" num!=0)
return(1/num)
if (fun=="dms")
return(dms(num))
if (fun=="deg")
return(deg(num))
if (fun=="~")
return(~num)
if (angle=="d")
{
if (fun=="sin")
return(sin(degressToRadians(num)))
if (fun=="cos")
return(cos(degressToRadians(num)))
if (fun=="tan")
return(tan(degressToRadians(num)))
if (fun=="arcsin" abs(num)=1)
return(radiansToDegress(asin(num)))
if (fun=="arccos" abs(num)=1)
return(radiansToDegress(acos(num)))
if (fun=="arctan")
return(radiansToDegress(atan(num)))
}
else
{
if (fun=="sin")
return(sin(num))
if (fun=="cos")
return(cos(num))
if (fun=="tan")
return(tan(num))
if (fun=="arcsin" abs(num)=1)
return(asin(num))
if (fun=="arccos" abs(num)=1)
return(acos(num))
if (fun=="arctan")
return(atan(num))
}
if (fun=="hypsin")
return((exp(num)-exp(0-num))*0.5)
if (fun=="hypcos")
return((exp(num)+exp(-num))*0.5)
if (fun=="hyptan")
return((exp(num)-exp(-num))/(exp(num)+exp(-num)))
if (fun=="ahypsin" | fun=="hypcos" | fun=="hyptan")
{
alert("对不起,公式还没有查到!")
return(num)
}
alert("超出函数定义范围")
return(num)
}
}
function factorial(n)
{
n=Math.abs(parseInt(n))
var fac=1
for (;n0;n-=1)
fac*=n
return(fac)
}
function dms(n)
{
var neg=(n0)
with(Math)
{
n=abs(n)
var d=floor(n)
var m=floor(60*(n-d))
var s=(n-d)*60-m
}
var dms=d+m/100+s*0.006
if (neg)
dms=-dms
return(dms)
}
function deg(n)
{
var neg=(n0)
with(Math)
{
n=abs(n)
var d=floor(n)
var m=floor((n-d)*100)
var s=(n-d)*100-m
}
var deg=d+m/60+s/36
if (neg)
deg=-deg
return(deg)
}
function degressToRadians(degress)
{
return(degress*Math.PI/180)
}
function radiansToDegress(radians)
{
return(radians*180/Math.PI)
}
//界面
//--
/script
/head
!--written by GoldHuman li hai--
!--2000.8--
body
div align="center"
form name=calc
table border="1" width="500" height="250"
tr
td height=50
table width=500
td
img src="../img/cp_logo.gif"
/td
td
div align=center
input type=text name="display" value="0" readonly size="40"
/div
/td
/table
/td
/tr
tr
td
table width=500
tr
td width=290
input type=radio name="carry" onClick="inputChangCarry(16)"
十六进制
input type=radio name="carry" checked onClick="inputChangCarry(10)"
十进制
input type=radio name="carry" onClick="inputChangCarry(8)"
八进制
input type=radio name="carry" onClick="inputChangCarry(2)"
二进制
/td
td
/td
td width=135
input type=radio name="angle" value="d" onClick="inputChangAngle('d')" checked
角度制
input type=radio name="angle" value="r" onClick="inputChangAngle('r')"
弧度制
/td
/tr
/table
table width=500
tr
td width=170
input name="shiftf" type="checkbox" onclick="inputshift()"上档功能
input name="hypf" type="checkbox" onclick="inputshift()"双曲函数
/td
td
input name="bracket" value="" type=text size=3 readonly style="background-color=lightgrey"
input name="memory" value="" type=text size=3 readonly style="background-color=lightgrey"
input name="operator" value="" type=text size=3 readonly style="background-color=lightgrey"
/td
td width=183
input type="button" value=" 退格 "
onclick="backspace()" style="color=red"
input type="button" value=" 清屏 "
onClick="document.calc.display.value = 0 " style="color=red"
input type="button" value=" 全清"
onClick="clearall()" style="color=red"
/td
/tr
/table
table width=500
tr
td
table
tr align=center
td
input name=pi type="button" value=" PI "
onClick="inputfunction('pi','pi')" style="color=blue"
/td
td
input name=e type="button" value=" E "
onClick="inputfunction('e','e')" style="color=blue"
/td
td
input name=bt type="button" value="d.ms"
onClick="inputfunction('dms','deg')" style="color=#ff00ff"
/td
/tr
tr align=center
td
input type="button" value=" ( "
onClick="addbracket()" style="color=#ff00ff"
/td
td
input type="button" value=" ) "
onClick="disbracket()" style="color=#ff00ff"
/td
td
input name=ln type="button" value=" ln "
onClick="inputfunction('ln','exp')" style="color=#ff00ff"
/td
/tr
tr align=center
td
input name=sin type="button" value="sin "
onClick="inputtrig('sin','arcsin','hypsin','ahypsin')" style="color=#ff00ff"
/td
td
input type="button" value="x^y "
onClick="operation('^',7)" style="color=#ff00ff"
/td
td
input name=log type="button" value="log "
onClick="inputfunction('log','expdec')" style="color=#ff00ff"
/td
/tr
tr align=center
td
input name=cos type="button" value="cos "
onClick="inputtrig('cos','arccos','hypcos','ahypcos')" style="color=#ff00ff"
/td
td
input name=cube type="button" value="x^3 "
onClick="inputfunction('cube','cubt')" style="color=#ff00ff"
/td
td
input type="button" value=" n! "
onClick="inputfunction('!','!')" style="color=#ff00ff"
/td
/tr
tr align=center
td
input name=tan type="button" value="tan "
onClick="inputtrig('tan','arctan','hyptan','ahyptan')" style="color=#ff00ff"
/td
td
input name=sqr type="button" value="x^2 "
onClick="inputfunction('sqr','sqrt')" style="color=#ff00ff"
/td
td
input type="button" value="1/x "
onClick="inputfunction('recip','recip')" style="color=#ff00ff"
/td
/tr
/table
/td
td width=30
/td
td
table
tr
td
input type="button" value=" 储存 "
onClick="putmemory()" style="color=red"
/td
/tr
td
input type="button" value=" 取存 "
onClick="getmemory()" style="color=red"
/td
/tr
tr
td
input type="button" value=" 累存 "
onClick="addmemory()" style="color=red"
/td
/tr
tr
td
input type="button" value=" 积存 "
onClick="multimemory()" style="color=red"
/td
/tr
tr
td height="33"
input type="button" value=" 清存 "
onClick="clearmemory()" style="color=red"
/td
/tr
/table
/td
td width=30
/td
td
table
tr align=center
td
input name=k7 type="button" value=" 7 "
onClick="inputkey('7')" style="color=blue"
/td
td
input name=k8 type="button" value=" 8 "
onClick="inputkey('8')" style="color=blue"
/td
td
input name=k9 type="button" value=" 9 "
onClick="inputkey('9')" style="color=blue"
/td
td
input type="button" value=" / "
onClick="operation('/',6)" style="color=red"
/td
td
input type="button" value="取余"
onClick="operation('%',6)" style="color=red"
/td
td
input type="button" value=" 与 "
onClick="operation('',3)" style="color=red"
/td
/tr
tr align=center
td
input name=k4 type="button" value=" 4 "
onClick="inputkey('4')" style="color=blue"
/td
td
input name=k5 type="button" value=" 5 "
onClick="inputkey('5')" style="color=blue"
/td
td
input name=k6 type="button" value=" 6 "
onClick="inputkey('6')" style="color=blue"
/td
td
input type="button" value=" * "
onClick="operation('*',6)" style="color=red"
/td
td
input name=floor type="button" value="取整"
onClick="inputfunction('floor','deci')" style="color=red"
/td
td
input type="button" value=" 或 "
onClick="operation('|',1)" style="color=red"
/td
/tr
tr align=center
td
input type="button" value=" 1 "
onClick="inputkey('1')" style="color=blue"
/td
td
input name=k2 type="button" value=" 2 "
onClick="inputkey('2')" style="color=blue"
/td
td
input name=k3 type="button" value=" 3 "
onClick="inputkey('3')" style="color=blue"
/td
td
input type="button" value=" - "
onClick="operation('-',5)" style="color=red"
/td
td
input type="button" value="左移"
onClick="operation('',4)" style="color=red"
/td
td
input type="button" value=" 非 "
onClick="inputfunction('~','~')" style="color=red"
/td
/tr
tr align=center
td
input type="button" value=" 0 "
onClick="inputkey('0')" style="color=blue"
/td
td
input type="button" value="+/-"
onClick="changeSign()" style="color=blue"
/td
td
input name=kp type="button" value=" . "
onClick="inputkey('.')" style="color=blue"
/td
td
input type="button" value=" + "
onClick="operation('+',5)" style="color=red"
/td
td
input type="button" value=" ＝ "
onClick="result()" style="color=red"
/td
td
input type="button" value="异或"
onClick="operation('x',2)" style="color=red"
/td
/tr
tr align=center
td
input name=ka type="button" value=" A "
onClick="inputkey('a')" style="color=blue" disabled=true
/td
td
input name=kb type="button" value=" B "
onClick="inputkey('b')" style="color=blue" disabled=true
/td
td
input name=kc type="button" value=" C "
onClick="inputkey('c')" style="color=blue" disabled=true
/td
td
input name=kd type="button" value=" D "
onClick="inputkey('d')" style="color=blue" disabled=true
/td
td
input name=ke type="button" value=" E "
onClick="inputkey('e')" style="color=blue" disabled=true
/td
td
input name=kf type="button" value=" F "
onClick="inputkey('f')" style="color=blue" disabled=true
/td
/tr
/table
/td
/tr
/table
/td
/tr
/table
/form
/div
/body
/html
如何用JS创建一个简单的网页计算器
!doctype html
html
head
title计算器/title
meta charset="utf-8"/
style type="text/css"
.panel{
border:4px solid #ddd;
width:192px;
margin:100px auto;
}
.panel p,.panel input{
font-family:"微软雅黑";
font-size:20px;
margin:4px;
float:left;
}
.panel p{
width:122px;
height:26px;
border:1px solid #ddd;
padding:6px;
overflow:hidden;
}
.panel input{
width:40px;
height:40px;
border:1px solid #ddd;
}
/style
script type="text/javascript"
//参数e用来接收传入的event对象
function cal(e){
//1.获取事件源，处理button的事件
var obj=e.srcElement||e.target;
if(obj.nodeName !="INPUT"){
return;
}
var value=obj.value;
var p=document.getElementById("screen");
if(value=="C"){
//2.如果是[C]，则清空p
p.innerText="";
}else if(value=="="){
//3.如果是[=]，则运算
var exp=p.innerText;
try{
var result=eval("("+exp+")");
//如果正确执行，将结果写入p
p.innerText=result;
}catch(e){
//发生错误，给予错误提示
p.innerText="Error.";
}
}else{
//4.如果是其它按钮，则将value追加到p中
p.innerText+=value;
}
}
/script
/head
body
!--在最外层的div上注册单击事件，传入event对象，然后在函数中通过event判断出事件来源于哪一个button，
进而做出应有的处理。这样的好处是，避免在button上大量的注册事件。--
div class="panel" onClick="cal(event);"
div
p id="screen"/p
input type="button" value="C"
div style="clear:both"/div
/div
div
input type="button" value="7"
input type="button" value="8"
input type="button" value="9"
input type="button" value="/"
input type="button" value="4"
input type="button" value="5"
input type="button" value="6"
input type="button" value="*"
input type="button" value="1"
input type="button" value="2"
input type="button" value="3"
input type="button" value="-"
input type="button" value="0"
input type="button" value="."
input type="button" value="="
input type="button" value="+"
div style="clear:both"/div
/div
/body
/html
这是我自学时候写的计算器
怎么在网页上制作一个简易计算器
(1)先画个页面，把每个数字 运算符号放进去；
(2)然后每个数字 符号绑定一个事件，这个事件获取数字或者符号的值，放进一个Input框；
(3)点击计算，把Input框的字符串表达式计算，eval("1*2")；
(4)还有计算前要对表达式进行校验,不规则的表达式不能计算。
用JS做一个简单的网页计算器如图所示，只进行简单的加减乘除运算
按顺序 123 分别设 id=a id=b id=c
var result = parseInt($("#a").val())+$("#b").val()+parseInt($("#c").val())
