按了等号怎么没有反应？
<script type="text/javascript">
function count(){
var txt1=parseInt(document.getElementById('txt1'）.value);
var txt2=parseInt(document.getElementById('txt2'）.value);
var result=document.getElementById('select'）.value);
var sum='';
switch(result){
case '+':
sum=txt1+txt2;
break;
case '-':
sum=txt1-txt2;
break;
case '*':
sum=txt1*txt2;
break;
case '/':
sum=txt1/txt2;
break;
}
document.getElementById('fruit').value=sum；
}
</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=' = ' oclick='count()'/> <!--通过 = 按钮来调用创建的函数，得到结果-->
