计算器无法计算结果，哪里出错了？-慕课网

计算器无法计算结果，哪里出错了？

来源：6-11 编程练习

LanceChou

2016-09-24 21:14

<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
   function count(){
   var a=document.getElementById("txt1").value;
   var b=document.getElementById("ttxt2").value;
   var s=document.getElementById("select").value;
   var h="";
   switch(s)
   {
        case "+":
        he=parseInt(a)+parseInt(b);
        break;
        case "-":
        he=parseInt(a)-parseInt(b);
        break;
        case "*":
        he=parseInt(a)*parseInt(b);
        break;
        default;
        he=parseInt(a)/parseInt(b);
   }
   document.getElementById("fruit").value=h;
   }
</script>
</head>
<body>
<input id="txt1" type="text" />
<select id="select">
    <option type="+">+</option>
    <option type="-">-</option>
    <option type="*">*</option>
    <option type="/">/</option>
</select>
<input id="txt2" type="text" />
<input type="button" value="=" onClick="count()"/>
<input id="fruit" type="text" />
</body>
</html>