哪里不对呢？
<script type="text/javascript">
function count(){
var txt1value=parselnt(document.getElementById("txt1").value);
var txt2value=parselntdocument.getElementById('txt2').value);
//获取第一个输入框的值
//获取第二个输入框的值
//获取选择框的值
var selectvalue=document.getElementById('select').value;
var zhi;
switch(selectvalue)
case "+":
zhi=txt1value+txt2value;
break;
case "-":
zhi=txt1value-txt2value;
break;
case "*":
zhi=txt1value*txt2value;
break;
case "/":
zhi=txt1value/txt2value;
break;
//获取通过下拉框来选择的值来改变加减乘除的运算法则
//设置结果输入框的值
$('fruit').value=(zhi);
}
</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>
</html>
