死活顯示不了輸出框的值，求解答！
<!DOCTYPE html>
<html>
?<head>
? <title> 事件</title>?
? <script type="text/javascript">
?? function count(){
????? var num1 = parsefloat(document.getElementById("txt1").value);
???? var num2 = parsefloat(document.getElementById("txt2").value);
???? var sel = document.getElementById("select").value;
?var result ;
??? switch(sel){
??????? case "+" :
?????????????? result = num1 + num2;
??????????? break;
??????? case "-" ：
????????????? result = num1 - num2;
?????????? break;
??????? case "*" :
????????????? result = num1 * num2;
??????????? break;
??????????? default :
???????????? result = num1 / num2;
??????????? ;
??? }
??? 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=' = ' onlick="count()"? /> <!--通過(guò) = 按鈕來(lái)調(diào)用創(chuàng)建的函數(shù)，得到結(jié)果-->
?? <input type='text' id='fruit'? />??
?</body>
</html>
2017-01-23
swith里的第二個(gè)case的冒號(hào)是中文的冒號(hào)