加法，减法，乘法不可以，结果显示undefined
<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
function count(){
var one=document.getElementById("txt1").value;
var two=document.getElementById("txt2").value;
var select=document.getElementById("select").value;
var result;
switch (select){
case '+':
result=parseFloat(one)+parseFloat(two);
break;
case '-':
result=parseFloat(one)-parseFloat(two);
break;
case '*':
result=parseFloat(one)*parseFloat(two);
break;
case '/':
reault=parseFloat(one)/parseFloat(two);
break;
}
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()" /> <!--通过 = 按钮来调用创建的函数，得到结果-->
<input type='text' id='fruit' />
</body>
</html>
