<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>计算器</title>
<!-- 计算器 sose 版权所有 version 1.0 2010-04-03 -->
</head>
<body>
<form name="calform" >
<table border="2" align="center" cellpadding="0" cellspacing="0" bordercolor="#666666">
<tr>
<td><table border="2" align="center" cellpadding="0" cellspacing="0" bordercolor="#FFFFFF" bgcolor="#99CCCC">
<tr align="center">
<td colspan="4" align="center">计算器</td>
</tr>
<tr align="center">
<td colspan="3"><input name="calout" type="text" value="0" style="text-align:right ; background-color:lightgrey" readonly="true"></td>
<td><input type="button" name="CE" value=" C E " onClick="init()"></td>
</tr>
<tr>
<td><input type="button" name="1" value=" 1 " onClick="press(1)"></td>
<td><input type="button" name="2" value=" 2 " onClick="press(2)"></td>
<td><input type="button" name="3" value=" 3 " onClick="press(3)"></td>
<td><input type="button" name="add" value=" + " onClick="operate('+')" ></td>
</tr>
<tr>
<td><input type="button" name="4" value=" 4 " onClick="press(4)"></td>
<td><input type="button" name="5" value=" 5 " onClick="press(5)"></td>
<td><input type="button" name="6" value=" 6 " onClick="press(6)"></td>
<td><input type="button" name="subtract" value=" - " onClick="operate('-')"></td>
</tr>
<tr>
<td><input type="button" name="7" value=" 7 " onClick="press(7)"></td>
<td><input type="button" name="8" value=" 8 " onClick="press(8)"></td>
<td><input type="button" name="9" value=" 9 " onClick="press(9)"></td>
<td><input type="button" name="multiply" value=" * " onClick="operate('*')"></td>
</tr>
<tr>
<td><input type="button" name="0" value=" 0 " onClick="press(0)"></td>
<td><input type="button" name="dot" value=" . " onClick="decimal()"></td>
<td><input type="button" name="=" value=" = " onClick="operate('=')"></td>
<td><input type="button" name="divide" value=" / " onClick="operate('/')"></td>
</tr>
</table></td>
</tr>
</table>
</form>
<script language="javascript">
var op = ""; //操作符
var calResult = 0; //计算结果
var flag = true; //false开始一个新的数据，在按operate之后将其置为false
function press(num){ //输入数据
if(flag){
if(document.calform.calout.value == "0"){ //此处若是用==0，则会出错
document.calform.calout.value = num;
}else{
document.calform.calout.value += num;
}
}else{
document.calform.calout.value = num;
flag = true;
}
}
function operate(tempop){
document.calform.dot.disabled = false;
if(tempop == "=" && calResult!=0 && flag == true){ //是=;{dy}个数不能为0,防止做被除数;按operate之后有输入第二个数
var secnum = parseFloat(document.calform.calout.value);
switch(op){
case '+':
calResult +=secnum;
break;
case '-':
calResult -=secnum;
break;
case '*':
calResult *=secnum;
break;
case '/':
if(secnum == 0){
calResult = "被除数不能为零";
}else{
calResult /=secnum;
}
break;
}
document.calform.calout.value = calResult; //显示计算结果
flag = false; //当继续输入数据时开始一个新的输入
}else{ //不是=，保存当前值和操作符
if(document.calform.calout.value == "0."){
calResult = 0;
}else{
calResult = parseFloat(document.calform.calout.value); //保存当前值
}
op = tempop; //保存操作符
flag = false; //开始一个新的输入
}
}
function decimal(){
if(flag){
if(document.calform.calout.value.indexOf(".") == -1){ //检查是否含有小数点
document.calform.calout.value += ".";
secNumFlag = true;
}
}else{
document.calform.calout.value = "0.";
flag = true;
secNumFlag = true;
}
check();
}
function init(){
op = ""; //xx操作数
document.calform.calout.value = 0; //显示为0，初始状态
calResult = 0; //保存{dy}个操作数的变量清零
flag = true; //开始输入一个新数
}
function delone(){ //删除一个数字
var str = document.calform.calout.value;
if(str.length>1){
document.calform.calout.value = str.substring(0,str.length-1);
}else{
document.calform.calout.value = 0;
}
check();
}
function keydowm(){
//alert(event.keyCode);
switch(event.keyCode){
case 8:
delone();break; //删除一位
case 106:
operate('*');break;
case 107:
operate('+');break;
case 109:
case 189:
operate('-');break;
case 190:
case 110:
decimal();break;
case 111:
operate('/');break;
case 187:
operate('=');break;
case 116:
break;
default :
if(parseInt(event.keyCode)>47 && parseInt(event.keyCode)<58){
press(parseInt(event.keyCode)-48);
}
break;
}
}
function check(){ //检查小数点，存在的话就使按钮失效，此检查有点鸡肋
if(document.calform.calout.value.indexOf('.',0) != -1){
document.calform.dot.disabled = true;
}else{
document.calform.dot.disabled = false;
}
}
document.onkeydown= keydowm,check;
document.onclick = check;
</script>
</body>
</html>
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