为何我输出的是个字符串啊
<!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 FH=document.getElementById("select").value;
var res="";
switch(FH){
case "+":
res=A+B;
break;
case "-":
res=A-B;
break;
case "*":
res=A*B;
break;
default:
res=A/B;
break;
}
document.getElementById("fruit").value=res;
}
</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' />
<p>为何我输出的是个字符串啊</p>
</body>
</html>
