大神们，我哪里出问题了？求助
<!DOCTYPE html>
<html>
<head>
<title>我的网页</title>
<meta charset="utf-8">
<script type="text/javascript">
function count(){
var a=parselnt(document.getElementById("txt1").value);
var b=parselnt(document.getElementById("txt2").value);
var c=document.getElementById("select").value;
var d;
switch(c){
case"+":
d=a+b;
break;
case"-":
d=a-b;
break;
case"*":
d=a*b;
break;
case"/":
d=a/b;
break;
default:
break;
}
document.getElementById("fruit").value=d;
}
</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>
