哪里有问题？
<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
function count(){
//获取第一个输入框的值
var num1=parseInt(document.getElementById("txt1").value);
//获取第二个输入框的值
var num2=parseInt(document.getElementById("txt2").value);
//获取选择框的值
var op=document.getElementById("select").value;
var result;
//获取通过下拉框来选择的值来改变加减乘除的运算法则
function count()
{
switch(op)
{
case "+":
result=num1+num2;
break;
case "-":
result=num1-num2;
break;
case "*":
result=num1*num2;
break;
case "/":
result=num1/num2;
break;
}
//设置结果输入框的值
alert(result);
document.getElementById("fruit").value=result;
}
</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' />
</body>
</html>
