在.php中写了js，中的内容无法运行出结果，请问如何修改
<script>
function Choice(number)
{
switch(num){
case 0:
location.href ="http://localhost/insert.php";
break;
case 1:
location.href ="http://localhost/update.php";
break;
case 2:
location.href ="http://localhost/delete.php";
break;
case 3:
location.href ="first.html";
break;
}
}
</script>
</head>
<body>
<?php
$db=mysqli_connect("localhost","root","181128","dataone");
if (!$db) {
die('Could not connect: ' . mysqli_connect_error());
}
echo 'Connected successfully <br/>';
mysqli_select_db($db,"dataone");
$result = mysqli_query($db,"select *
FROM airplanes");
print"<table>";
if(mysqli_fetch_assoc($result)==0)
{
echo"暂无信息";
}
else{
、、、、、、、、
}
}
print"</table>";
mysqli_close($db);
?>
<hr/>
<input type="button" value="添加" onclick="Choice(0)"/>
<input type="reset" value="重置"/>
<input type="button" value="修改" onclick="Choice(1)"/>
<input type="button" value="删除" onclick="Choice(2)"/>
<input type="button" value="退出" onclick="Choice(3)"/>
</body>
onclick有这个事件吗？