                        課程
                    
                        /前端開發
                        
                            /JavaScript
                        
                        /JavaScript進階篇

幫忙看看，哪里出錯了。

<!DOCTYPE?html>
<html>
?<head>
??<title>?事件</title>??
??<script?type="text/javascript">
???function?count(){
????var?txt1=?document.getelementById("txt1").value;??
????var?txt2=?document.getelementById("txt2").value;
????var?ysf?=?document.getelementById("select").value;
????var?jg;
????switch(ysf)
????{
????????case:"+"
????????jg=parseFloat(txt1)+parseFloat(txt2);
????????break;
????????case:"-"
????????jg=parseInt(txt1)-parseInt(txt2);
????????break;
????????case:"*"
????????jg=parseInt(txt1)*parseInt(txt2);
????????break;
????????case:"/"
????????jg=parseInt(txt1)/parseInt(txt2);
????????break;
????????case:"%"
????????jg=parseInt(txt1)%parseInt(txt2);
????????default:
????}
???????document.getelementById("fruit").value=jg;
????//獲取第一個輸入框的值
	//獲取第二個輸入框的值
	//獲取選擇框的值
	//獲取通過下拉框來選擇的值來改變加減乘除的運算法則
????//設置結果輸入框的值?
????
???}
??</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()"/>?<!--通過?=?按鈕來調用創建的函數，得到結果-->?
???<input?type='text'?id='fruit'?/>???
?</body>
</html>