功能实现:
能够实现简单的加、减、乘、除、求余计算,可以进行带小数点和正负数的计算,C为清零按钮,CE为退格按钮。
界面截图:
页面布局代码:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>计算器</title>
<style>
table tr td{width:100px; height:60px; text-align:center;}
#display{width:306px; height:60px; font-size:32px; text-align:right; background-color:#CCC; color:#666;}
.btn{width:80px; height:40px;}
</style>
<script src="calculator.js"></script>
</head>
<body>
<form>
<table border="1" align="center">
<tr>
<td colspan="3"><input type="text" id="display" readonly="readonly" value="0" /></td>
<td><input type="button" class="btn" value="C" οnclick="clearscreen()" /></td>
<td><input type="button" class="btn" value="CE" οnclick="del()" /></td>
</tr>
<tr>
<td><input type="button" class="btn" value="7" οnclick="command(7)" /></td>
<td><input type="button" class="btn" value="8" οnclick="command(8)" /></td>
<td><input type="button" class="btn" value="9" οnclick="command(9)" /></td>
<td><input type="button" class="btn" value="+/-" οnclick="pm()" /></td>
<td><input type="button" class="btn" value="%" οnclick="persent()" /></td>
</tr>
<tr>
<td><input type="button" class="btn" value="4" οnclick="command(4)" /></td>
<td><input type="button" class="btn" value="5" οnclick="command(5)" /></td>
<td><input type="button" class="btn" value="6" οnclick="command(6)" /></td>
<td><input type="button" class="btn" value="+"οnclick="plus()" /></td>
<td><input type="button" class="btn" value="-"οnclick="minus()" /></td>
</tr>
<tr>
<td><input type="button" class="btn" value="1" οnclick="command(1)" /></td>
<td><input type="button" class="btn" value="2" οnclick="command(2)" /></td>
<td><input type="button" class="btn" value="3" οnclick="command(3)" /></td>
<td><input type="button" class="btn" value="*"οnclick="times()" /></td>
<td><input type="button" class="btn" value="/"οnclick="divide()" /></td>
</tr>
<tr>
<td><input type="button" class="btn" value="0" οnclick="command(0)" /></td>
<td><input type="button" class="btn" value="." οnclick="dot()" /></td>
<td id="test"></td>
<td><input type="button" class="btn" value="=" οnclick="equal()" /></td>
<td><input type="button" class="btn" value="返回" /></td>
</tr>
</table>
</form>
</body>
</html>
JavaScript代码:
var num1=0,results=0,num2=0;
var operate=0; //判断输入状态的标志
var calcul=""; //判断计算状态的标志
function command(num){
var str=String(document.getElementById("display").value); //获得当前显示数据
str=(str!="0") ? ((operate==0) ? str : "") : ""; //如果当前值不是"0",且状态为0,则返回当前值,否则返回空值;
str=str+num; //给当前值追加字符
document.getElementById("display").value=str; //刷新显示
operate=0;
}
function clearscreen(){ //清除数据
num1=0;
results=0;
num2=0;
operate=0;
calcul="";
document.getElementById("display").value="0";
document.getElementById("test").innerText="";
}
function del(){ //退格
var str=String(document.getElementById("display").value);
str=(str!="0") ? ((operate==0) ? str : "0") : "0";
str=(str!="0")?str:"";
str=str.substr(0,str.length-1);
str=(str!="")?str:"0";
document.getElementById("display").value=str;
}
function dot(){
var str=String(document.getElementById("display").value);
str=(str!="0") ? ((operate==0) ? str : "0") : "0"; 如果当前值不是"0",且状态为0,则返回当前值,否则返回"0";
for(i=0;i<=str.length;i++){
if(str.substr(i,1)=="."){
return false;
}
}
str=str+".";
document.getElementById("display").value=str;
operate=0;
}
function pm(){
var str=String(document.getElementById("display").value);
str=(str!="0") ? ((operate==0) ? str : "0") : "0";
if(str!="0"){
if(str.substr(0,1)=="-"){
str=str.substr(1,str.length-1);
}else{
str="-"+str;
}
}else{
str="0";
}
document.getElementById("display").value=str;
operate=0;
}
function plus(){ //加法
num1=Number(document.getElementById("display").value);
operate=1; //更改输入状态
calcul="+"; //更改计算状态为加
command(num)
}
function minus(){ //减法
num1=Number(document.getElementById("display").value);
operate=1; //更改输入状态
calcul="-";
command(num)
}
function times(){ //乘法
num1=Number(document.getElementById("display").value);
operate=1; //更改输入状态
calcul="*";
command(num)
}
function divide(){ //除法
num1=Number(document.getElementById("display").value);
operate=1; //更改输入状态
calcul="/";
command(num)
}
function persent(){ //求余
num1=parseFloat(document.getElementById("display").value);
operate=1; //更改输入状态
calcul="%";
command(num)
}
function equal(){
num2=parseFloat(document.getElementById("display").value);
calculate(num1,num2,calcul); //等于
operate=1;
calcul="";
num1=0;
num2=0;
results=0;
}
function calculate(num1,num2,calcul){
switch(calcul){ //判断要输入状态
case "+":
results=num1+num2;
break; //计算"+"
case "-":
results=num1-num2;
break; //计算"-"
case "*":
results=num1*num2;
break;
case "/":
if(num2!=0){
results=num1/num2;
}else{
alert("除数不为0!");
}
break;
case "%":
results=num1%num2;
break;
}
document.getElementById("test").innerText=String(num1)+calcul+String(num2);
document.getElementById("display").value=String(results);
}