js练习计算器，支持鼠标点击、键盘操作
<!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2.2</title> </head> <body> <input id="a1" disabled="disabled" />
<input id="a2" disabled="disabled" />
<input id="a3" disabled="disabled" /> <p id="counter"></p> <script type="text/javascript">
function addnum(id)
{
b2 = document.getElementById("a2").value;
if(!b2){
document.getElementById("a1").value += id;
}else{
document.getElementById("a3").value += id;
}
} function addtype(id)
{
b1 = document.getElementById("a1").value;
if(!b1){
alert("请输入数字1");
return false;
}
if(id=='*'){
type = '×';
}else if(id=='/'){
type = '÷';
}else{
type = id;
}
document.getElementById("a2").value = type;
} function backspace()
{
b1 = document.getElementById("a1").value;
b2 = document.getElementById("a2").value;
b3 = document.getElementById("a3").value; if(b3){
b3 = b3.substring(0,b3.length-1);
document.getElementById("a3").value = b3;
}else if(b2){
b2 = b2.substring(0,b2.length-1);
document.getElementById("a2").value = b2;
}else if(b1){
b1 = b1.substring(0,b1.length-1);
document.getElementById("a1").value = b1;
}
} function clean()
{
document.getElementById("a1").value="";
document.getElementById("a2").value="";
document.getElementById("a3").value="";
} function suan()
{
var b1 = document.getElementById("a1").value;
var b2 = document.getElementById("a2").value;
if(b2=="×"){
b2 = "*";
}else if(b2=="÷"){
b2 = '/';
}
var b3 = document.getElementById("a3").value;
var bbb = new Array(["+"],["-"],["*"],["/"]); if(!b1){
alert("请输入数字1");
return false;
}
if(b2!=bbb[0] && b2!=bbb[1] && b2!=bbb[2] && b2!=bbb[3]){
alert("请输入运算符");
return false;
}
if(!b3){
alert("请输入数字2");
return false;
}
if(b2==bbb[0]){
var b4=Number(b1)+Number(b3);
}
else if(b2==bbb[1]){
var b4=Number(b1)-Number(b3);
}
else if(b2==bbb[2]){
//js乘法不精确会有很多小数点，整体乘一个数再除去它
b1 = Number(b1)*10000;
b3 = Number(b3)*10000;
b4=b1*b3/100000000;
b1 = b1/10000;
b3 = b3/10000;
}
else if(b2==bbb[3]){
if(b3==0){
b4="[除数不能为零]";
}else{
b4 = Math.round(Number(b1)/Number(b3));
var b5=Number(b1)%Number(b3);
b4=b4+" 余数"+b5;
}
}
if(b2=="*"){
b2 = "×";
}else if(b2=="/"){
b2 = '÷';
}
document.getElementById("counter").innerHTML = b1+b2+b3+"="+b4;
document.getElementById("a1").value="";
document.getElementById("a2").value="";
document.getElementById("a3").value="";
} //keyCode对应键位
keyarr = new Array()
//数字
keyarr[48] = keyarr[96] = "0";
keyarr[49] = keyarr[97] = 1;
keyarr[50] = keyarr[98] = 2;
keyarr[51] = keyarr[99] = 3;
keyarr[52] = keyarr[100] = 4;
keyarr[53] = keyarr[101] = 5;
keyarr[54] = keyarr[102] = 6;
keyarr[55] = keyarr[103] = 7;
keyarr[56] = keyarr[104] = 8;
keyarr[57] = keyarr[105] = 9;
keyarr[110] = keyarr[190] = ".";
//运算符
keyarr[107] = "+";
keyarr[109] = "-";
keyarr[106] = "*";
keyarr[111] = "/";
//退格
keyarr[8] = "backspace";
//结果
keyarr[13] = "="; /*键盘事件*/
var isPiss = 0;
document.onkeydown = function(event) {
var e = event || window.event || arguments.callee.caller.arguments[0];
id = keyarr[e.keyCode];
if(id){
if(id=="+" || id=="-" || id=="*" || id=="/"){ //运算
addtype(id);
}else if(id=="backspace"){ //退格
backspace();
}else if(id=="="){ //结果
suan();
}else{ //输入数字
addnum(id);
}
}
};
</script> <style>
.clear {clear:both; height:0 !important; width:0 !important; overflow:hidden; font-size:0;}
.jisuanqi {width:303px; height:450px; background:#000; overflow:hidden; -webkit-user-select:none; -moz-user-select:none; -ms-user-select:none; user-select:none; font-family:"Microsoft Yahei";}
.jrow {padding-bottom:5px;}
.num, .type {width:72px; height:86px; overflow:hidden; line-height:86px; text-align:center; float:left; color:#fff; font-size:38px; cursor:pointer;}
.num {background:#343432; margin-right:5px;}
.num:active {background:#181818;}
.type {background:#181818;}
.type:active {background:#343432;}
.clean, .backspace {width:149px; height:86px; overflow:hidden; line-height:86px; text-align:center; color:#fff; font-size:38px; cursor:pointer;}
.clean {background:#343432; float:left;}
.clean:active {background:#181818;}
.backspace {background:#181818; float:right;}
.backspace:active {background:#343432;}
</style> <div class="jisuanqi">
<div class="jrow">
<div class="num" onclick="addnum(7)">7</div>
<div class="num" onclick="addnum(8)">8</div>
<div class="num" onclick="addnum(9)">9</div>
<div class="type" onclick="addtype('/')">÷</div>
<div class="clear"></div>
</div> <div class="jrow">
<div class="num" onclick="addnum(4)">4</div>
<div class="num" onclick="addnum(5)">5</div>
<div class="num" onclick="addnum(6)">6</div>
<div class="type" onclick="addtype('*')">×</div>
<div class="clear"></div>
</div> <div class="jrow">
<div class="num" onclick="addnum(1)">1</div>
<div class="num" onclick="addnum(2)">2</div>
<div class="num" onclick="addnum(3)">3</div>
<div class="type" onclick="addtype('-')">-</div>
<div class="clear"></div>
</div> <div class="jrow">
<div class="num" onclick="addnum('.')">.</div>
<div class="num" onclick="addnum(0)">0</div>
<div class="num" onclick="suan()">=</div>
<div class="type" onclick="addtype('+')">+</div>
<div class="clear"></div>
</div> <div class="jrow">
<div class="clean" onclick="clean()">C</div>
<div class="backspace" onclick="backspace()">←</div>
<div class="clear"></div>
</div>
</div> </body>
</html>