成功了，最后结果能返回到第三个文本框-慕课网

成功了，最后结果能返回到第三个文本框

来源：6-11 编程练习

qq_慕先生0585124

2019-11-12 14:39

<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
   function count(){

    var num1,num2,fuhao,jieguo;

    var fuhao=document.getElementById('select').value;
    var num1=parseInt(document.getElementById('txt1').value);
    var num2=parseInt(document.getElementById('txt2').value);
    switch(fuhao){
        case "+" :
            jieguo=num1+num2;
            break;
        case "-" :
            jieguo=num1-num2;
            break;
        case "*" :
            jieguo=num1*num2;
            break;
        case "/" :
            jieguo=num1/num2;
            break;
   }
    document.getElementById('fruit').value = jieguo;
    alert(jieguo);
}
</script>
</head>
<body>
   <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='count()' /> 
   <input type='text' id='fruit' value="结果"/>

</body>
</html>