怎么就不行了呢？？？？？？
<!DOCTYPE html>
<html>
<head>
<title>事件</title>
<script type="text/javascript">
function count(){
var a=document.getElementById("txt1").value;
var b=document.getElementById("txt2").value;
var c=document.getElementById("select").value;
var q="";
switch(c){
case "+":
q=parseInt(a)+parseInt(b);
break;
case "-":
q=a-b;
break;
case "*":
q=a*b;
break;
default:
q=a/b;
}
document.getElementById("fruit").value=q;
}
</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=' = ' coclick="count()"/> <!--通过 = 按钮来调用创建的函数，得到结果-->
<input type='text' id='fruit'/>
</body>
</html>
