用JS写的简单的计算器
参加某公司的面试后，有一机试题目：用web技术开发一个B/S结构的公式解析器。于是想了想思路，神来一笔想先写个计算器程序做基础，于是便写了这个程序。 function commonMath(){
1.本页效果图片 2.美化后的效果
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<script>
Array.prototype.remove=function(index)
{
if(isNaN(index)||index>this.length){return false;}
for(var i=0,n=0;i<this.length;i++)
{
if(this[i]!=this[index])
{
this[n++]=this[i]
}
}
this.length-=1
}
//类初始化
this.init = function(){
this.tmp = '';
this.debug = 0;
this.output = '';
this.method = '';
this.sign = 1;//0:-;1:+
this.register = Array();//寄存器
}
//设置报错信息
this.showmsg = function(msg){
if(this.debug == 1) alert(msg);
}
//设置运算符
this.setMethod = function(_method){
this.method = _method;
_length = this.register.length;
if(_length == 0){
if(this.tmp == '') return;
this.register[0] = this.tmp;
this.register[1] = _method;
this.tmp = '';
return;
}
if(_length = 2 || this.tmp == ''){
this.register[1] = _method;
}
if(_length == 2 && this.tmp != ''){
this.register[2] = this.tmp;
this.run(1);
}
if(_length == 3) this.run(1);
}
//设置显示值
this.setValue = function(_value){
var tmp = parseInt(eval(this.tmp+'+"'+_value+'"'));
max = /^-?\d{1,9}$/i;
if( max.test(tmp) == false){
return;
}
this.tmp = tmp;
this.output.value = this.tmp;
}
//设置符号
this.setSign = function(){
var del = 0;
var sign = Array('-','+');
this.sign = this.sign ^ 1;
_sign = sign[this.sign];
if(/\d/i.test(this.tmp)== false && this.register.length > 0){
del = 1;
this.tmp = this.register[0];
}
if(_sign == '-'){
this.tmp = -this.tmp;
}else{
this.tmp = Math.abs(this.tmp);
}
this.output.value = this.tmp;
if(del == 1){
this.register[0] = this.tmp;
this.tmp = '';
}
}
//获取按键
this.getValue = function(input){
var _in = input;
var inputList = document.getElementsByTagName("input");
this.output = inputList[0];
regMethod = /^[\+|\-|\*|\/]$/i;
if(regMethod.test(_in)){
this.setMethod(_in);
return;
}
regNum = /^\d$/i;
if(regNum.test(_in)){
this.setValue(_in);
return;
}
regSign = /^\+\/\-$/i;
if(regSign.test(_in)){
this.setSign(_in);
return;
}
regResult = /^=$/;
if(regResult.test(_in)){
this.run();
return;
}
}
//计算结果
this.run = function(type){
if(this.register.length < 2) return this.showmsg(1);
if(this.register.length == 2 && (this.tmp == '')) return this.showmsg(2);
if(this.register.length == 2 && this.tmp != ''){
this.register[2] = this.tmp;
this.run();
}
this.showmsg(this.register.join(' '));
var _exp = parseInt(eval(this.register.join(' ')));
this.output.value = _exp;
for(i=0;i<3;i++){
this.register.remove(i);
}
this.register[0] = _exp;
this.tmp = '';
if(type) this.register[1] = this.method;
return;
}
}
var commonMath = new commonMath();
commonMath.init();
</script>
<style>
#main{
width:100%;
height:100%;
}
#inputs{
position:relative;
top:50%;
left:50%;
}
.inbutton{
width:30px;
}
.outbutton{
width:145px;
text-align:right;
}
.tcenter{
text-align:center;
}
</style>
</head>
<body>
<div id="main">
<div>
<span class="outbutton tcenter">etongchina@gmail.com</span>
</div>
<div>
<span><input id="output" type="text" class="outbutton" maxlength="9" value="." /></span>
</div>
<div>
<span><input type="button" class="inbutton" value="7" onclick="commonMath.getValue(this.value)" /></span>
<span><input type="button" class="inbutton" value="8" onclick="commonMath.getValue(this.value)" /></span>
<span><input type="button" class="inbutton" value="9" onclick="commonMath.getValue(this.value)" /></span>
<span><input type="button" class="inbutton" value="+" onclick="commonMath.getValue(this.value)" /></span>
</div>
<div>
<span><input type="button" class="inbutton" value="4" onclick="commonMath.getValue(this.value);" /></span>
<span><input type="button" class="inbutton" value="5" onclick="commonMath.getValue(this.value);" /></span>
<span><input type="button" class="inbutton" value="6" onclick="commonMath.getValue(this.value);" /></span>
<span><input type="button" class="inbutton" value="-" onclick="commonMath.getValue(this.value);" /></span>
</div>
<div>
<span><input type="button" class="inbutton" value="1" onclick="commonMath.getValue(this.value);" /></span>
<span><input type="button" class="inbutton" value="2" onclick="commonMath.getValue(this.value);" /></span>
<span><input type="button" class="inbutton" value="3" onclick="commonMath.getValue(this.value);" /></span>
<span><input type="button" class="inbutton" value="*" onclick="commonMath.getValue(this.value);" /></span>
</div>
<div>
<span><input type="button" class="inbutton" value="0" onclick="commonMath.getValue(this.value);" /></span>
<span><input
type="button" class="inbutton" value="+/-"
onclick="commonMath.getValue(this.value);" /></span>
<span><input type="button" class="inbutton" value="." onclick="commonMath.getValue(this.value);" /></span>
<span><input type="button" class="inbutton" value="/" onclick="commonMath.getValue(this.value);" /></span>
</div>
<div>
<span><input
type="button" class="outbutton tcenter" value="计算"
onclick="commonMath.getValue('=');" /></span>
</div>
</div>
</body>
</html>
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