<script type="text/javascript">
function count(){
var txt1 = document.getElementById("txt1").value;
var txt2 = document.getElementById("txt2").value;
var select = document.getElementById("select").value;
var kk ="";
switch (select)
{
case "+":
kk = txt1 + txt2;
break;
case "-":
kk =txt1 - txt2;
break;
case "*":
kk = txt1 * txt2'
break;
case "/":
kk =txt1 / txt2;
break;
}
document.getElementById("fruit").value = kk;
}
</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()" /> <!--通过 = 按钮来调用创建的函数，得到结果-->
<input type='text' id='fruit' />
</body>
