<?php
session_start();
include("conn.php");
$username=$_GET["username"];
if($username==""){
echo "<script language=javascript>alert('用户名还没有输入！');window.close();</script>";
}
else{
$query=$mysqli->query("select * from tb_reader where username='$username'");
$result=$query->fetch_array();
if($result!=false){
echo "<script language=javascript>alert('用户名和系统中的重复！');window.close();</script>";
}
else{
echo "<script language=javascript>alert('恭喜！该用户名可以注册！！');window.close();</script>";

}
}
?>