                        課程
                    
                        /前端開(kāi)發(fā)
                        
                            /JavaScript
                        
                        /JavaScript進(jìn)階篇

代碼錯(cuò)誤何在？

<!DOCTYPE?html>
<html>
?<head>
??<title>?事件</title>??
??<script?type="text/javascript">
???function?count(){
????//獲取第一個(gè)輸入框的值
????var?a=document.getElementById("txt1").value;
????//獲取第二個(gè)輸入框的值
????var?b=document.getElementById("txt2").value;
????//獲取選擇框的值
????var?d=document.getElementById("select").value;
????//獲取通過(guò)下拉框來(lái)選擇的值來(lái)改變加減乘除的運(yùn)算法則
????var?e="";
????switch(d){
????case?"+":
???????e=parseFloat(a)+parseFloat(b);
???????break;
????case?"-"
???????e=parseFloat(a)-parseFloat(b);
???????break;
????case?"*":
???????e=parseFloat(a)*parseFloat(b);
???????break;
????case?"/":
???????e=parseFloat(a)/parseFloat(b);
????}
???//設(shè)置結(jié)果輸入框的值?
??????document.getElementById("fruit").value=e;
???}
??</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(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>