<!DOCTYPE?html>
<html>
?<head>
??<title>計算器</title>??
??<script?type="text/javascript">
???function?count(){
???????
????//獲取第一個輸入框的值
????var?first=document.getElementById('txt1').value;
//獲取第二個輸入框的值
????var?second=document.getElementById('txt2').value;
//獲取選擇框的值
????var?select1=document.getElementById('select').value;
//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(shè)置結(jié)果輸入框的值?
var?val;
switch?(select1)
{
?case?'+'?:
????val=first?+?second;break;
?????case?'-'?:
????val=first?-?second;break;
case?'*'?:
????val=first?*?second;break;
case?'/'?:
????val=first?/?second;break;
}
document.getElementById('fruit').value=val;
???}
???
</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(diào)用創(chuàng)建的函數(shù)，得到結(jié)果-->?
???<input?type='text'?id='fruit'?/>???
?</body>
</html>
夭壽啦，1+2=12啦。我做計算器的時候，加法默認(rèn)為字符串的連接怎么破
秋高水長
2016-03-12 12:12:12
