急，在线等。弹不出结果。

<!DOCTYPE HTML>
<html>

   <head>

       <meta charset="utf-8"/>
       <title>6编程练习</title>

   </head>

   <body>

       <script type="text/javascript">

           function tong(){
               var a = parseInt(document.getElementById)("txt1").value);
               var b = document.getElementById)("select").value;
               var c = parseInt(document.getElementById)("txt2").value);
               var result;
               switch(b){
               case "+":
                   result = a + c;
                   break;
               case "-":
                   result = a - c;
                   break;
               case "*":
                   result = a * c;
                   break;
               default:
                   result = a / c;
               }
               document.getElementById("adc").value = result;
           }


       </script>
       <input type="text" id="txt1"/>
       <select id="select">

           <option value="+">+</option>
           <option value="-">-</option>
           <option value="*">*</option>
           <option value="/">/</option>

       </select>
       <input type="text" id="txt2"/>
       <input type="button" value="=" onclick="tong()"/>
       <input type="text" id="adc"/>

   </body>
</html>

同7七

浏览 1186回答 2

急，在线等。弹不出结果。

2回答