原生JavaScript制作计算器

原生JavaScript制作计算器

<!DOCTYPE html>
<html>
 <head>
 <meta charset="UTF-8">
 <title></title>
 </head>
 <body>
 <!--第一个数X-->
 X:<input type="text" id="inp1" value="" /><br />
 <!--符号-->
 F:<input type="text" id="inp2" value="" /><br />
 <!--第二个数Y-->
 Y:<input type="text" id="inp3" value="" /><br />
 <!--结果R-->
 R:<input type="text" id="inp4" value="" /><br />
 <!--点击按钮-->
 <input type="submit" name="btn" id="btn" value="请计算" />
 </body>
 <script type="text/javascript">
 var inpX1 = document.getElementById("inp1");
 var inpF1 = document.getElementById("inp2");
 var inpY1 = document.getElementById("inp3");
 var inpR = document.getElementById("inp4");
 var result = document.getElementById("btn");
 var inpX ;
 var inpY ;
 var inpF ;
 var sum;
// 点击事件
 result.onclick = function(){
  inpX = Number(inpX1.value);
  inpF = inpF1.value;
  inpY = Number(inpY1.value);
  switch (inpF){
  case "+":{
   sum = inpX + inpY;
   break;
  }
  case "-":{
   sum = inpX - inpY;
   break;
  }
  case "*":{
   sum =inpX * inpY;
   break;
  }
  case "/":{
   sum = inpX / inpY;
   break;
  }
  default:{
   alert("请输入加减乘除中的任意一个");
   break;
  }
  }
  inpR.value = sum.toFixed(2);

 }
 </script>
</html>

再给大家分享一个稍微复杂些的计算器

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<style>
body,ul{ margin:0px; padding:0px;}
body{ background:#AF6332}
li{ list-style:none;}
.fl{ float:left;}
.fr{ float:right;}
.clearfix:after{ content:""; display:block;clear:both}
.clearfix{zoom:1;}
/*是用inset可以将外部阴影改成内部阴影;若要实现内外阴影同时存在，将其并在一行用逗号隔开*/
.calBox{ width:460px; padding-bottom:10px;background:#FDFDFD; border-radius:5px; position:absolute; left:50%; top:50%; margin-left:-230px; margin-top:-225px; box-shadow:0px 0px 10px rgba(0,0,0,0.8),0px 0px 10px rgba(0,0,0,0.5) inset; -webkit-box-shadow:0px 0px 10px rgba(0,0,0,0.8),0px 0px 10px rgba(0,0,0,0.5) inset; background:#F9F9F9; overflow:hidden}
input{ width:406px; height:82px; margin:10px 7px 0px; border-radius:5px; border:1px solid #64655F; box-shadow:0px 5px 2px rgba(157,157,145,0.8) inset; -webkit-box-shadow:0px 5px 2px rgba(157,157,145,0.8) inset; outline:none; background:#FCFDEB; text-align:right; font-family:"微软雅黑"; font-size:40px; padding:0px 10px;}
ul{}
li{ list-style:none; width:74px; height:34px; line-height:34px; text-align:center; font-family:"微软雅黑"; border:1px solid #8B8B8B; border-radius:5px; background:url(img/calBg) repeat-x; float:left; margin:12px 6px 0px;}
.one li{ height:44px; background:url(calBg1.jpg) repeat-x; line-height:44px;cursor:pointer;}
.one .orange{ background:url(calBg2.jpg) repeat-x; border:1px solid #875733;}
.one .black{ background:url(calBg3.jpg) repeat-x; border:1px solid #363636; color:#fff;}
.one .gray{ background:url(calBg4.jpg) repeat-x; border:1px solid #5F6366;}
.zero{ width:160px;}
.one .deng{ background:url(calBg5.jpg); height:100px;}
.twoBox{ width:353px; overflow:hidden; }
.two{ width:358px;}
.calBox .three { margin:0px}
.calu{ padding:0px 10px; width:470px;}
</style>
<script>
function findArr(a,c){for(var b=0;b<a.length;b++){if(a[b]==c){return true}}return false}function getClass(d,f){if(document.getElementsByClassName){return d.getElementsByClassName(f)}else{var a=[];var e=document.getElementsByTagName("*");for(var c=0;c<e.length;c++){var b=e[c].className.split(" ");if(findArr(b,f)){a.push(e[c])}}return a}};
window.onload=function()
{
	var aNum=getClass(document,'num');
	var oText=document.getElementById('text');
	var aPer=getClass(document,'oper');
	var oPer=document.getElementById('per');
	var oText1=document.getElementById('text1');
	var oDeng=getClass(document,'deng')[0];
	var oSq=getClass(document,'sq')[0];
	var oRec=getClass(document,'rec')[0];
	var oZheng=getClass(document,'zheng')[0];
	var oOn=getClass(document,'on')[0];
	var oOff=getClass(document,'off')[0];
	var oClea=getClass(document,'clea')[0];
	var bOnOrOffClick=false;	

	function fnNum(a)
	{		

		var bClear=false;
		oText.value='0'	

		for(var i=0;i<aNum.length;i++)
		{
			aNum[i].onclick=function()
			{
				if(!bOnOrOffClick)return;

				if(bClear)
				{					

					bClear=false;
				}

				if(oText.value.indexOf('.')!=-1)
				{
					if(this.innerHTML=='.')
					{
						return;
					}
				}
				if(oPer.value&&oText.value&&oText1.value=='')
				{
					oText1.value=oText.value;
					oText.value='';
				}	

				var re=/^0\.{1}\d+$/;
				var re1=/^([0]\d+)$/;
				oText.value+=this.innerHTML;

				if(re.test(oText.value))
				{
					return;
				}

				if(re1.test(oText.value))
				{
					oText.value=this.innerHTML;
				}
			}
			//符号部分的添加
			for(var j=0;j<aPer.length;j++)
			{
				aPer[j].onclick=function()
				{					

					if(oText.value&&oPer.value&&oText1.value)
					{
						var n=eval(oText1.value+oPer.value+oText.value);
						oText.value=n;
						oText1.value='';
					}
					oPer.value=this.innerHTML;
				}

			}
			//点击等号的时候
			oDeng.onclick=function()
			{
				//+-*/%的情况
				if(oText1.value==''&&oPer.value==''&&oText.value=='')
				{
					return;
				}
				var n=eval(oText1.value+oPer.value+oText.value);
				oText.value=n;
				oText1.value='';
				oPer.value='';
				bClear=true;
			}
			//点击开根号的时候
			oSq.onclick=function()
			{
				var m=Math.sqrt(oText.value);
				oText.value=m;
			}
			//点击倒数的时候
			oRec.onclick=function()
			{
				var a=1/oText.value;

				if(oText.value=='0')
				{
					a='正无穷'
				}
				oText.value=a;
			}
			//正负号的时候
			oZheng.onclick=function()
			{
				if(oText.value>0)
				{
					oText.value=-oText.value;
				}
				else
				{
					oText.value	=-oText.value;
				}
			}
			//清屏的时候
			oClea.onclick=function()
			{
				oText.value='0';
				oText1.value='';
				oPer.value='';
			}
		}
	}
	//on时
	oOn.onclick=function()
	{
		bOnOrOffClick=true;
		fnNum(bOnOrOffClick);
	}	

	//off时
	oOff.onclick=function()
	{
		bOnOrOffClick=false;
		fnNum(bOnOrOffClick);
		oText.value='';
	}
}
</script>
</head>

<body>
<div class="calBox">
  <div class="calu">
  	<input type="text" id="text">
    <ul class="one clearfix">
      <li class="orange on">开机</li>
      <li class="orange off">关机</li>
      <li class="orange clea">清屏</li>
      <li class="black zheng">+/-</li>
      <li class="black rec">1/x</li>
      <li class="num">7</li>
      <li class="num">8</li>
      <li class="num">9</li>
      <li class="gray oper">/</li>
      <li class="black oper">%</li>
      <li class="num">4</li>
      <li class="num">5</li>
      <li class="num">6</li>
      <li class="gray oper">*</li>
      <li class="black sq">√</li>
      <!-- -->
    </ul>
    <div class="clearfix">
      <div class="twoBox fl">
      	<ul class="one fl two">
          <li class="num">1</li>
          <li class="num">2</li>
          <li class="num">3</li>
          <li class="gray oper">-</li>
          <li class="zero num">0</li>
          <li class="num">.</li>
          <li class="gray oper">+</li>
        </ul>
      </div>
      <ul class="one three clearfix fl">
        <li class="black deng fl">=</li>
      </ul>
    </div>
  </div>
</div>
<input type="text" id="per" style="display:none">
<input type="text" id="text1" style="display:none">
</body>
</html>

效果图演示