<form action="connet.php" method="POST" >
用戶名：<input type = "text" name = "username"/> <br />
密碼：<input type = "password" name="password"/> <br />
重復(fù)密碼：<input type = "password" name="repassword"/><br />
<input type = "submit" value = "提交"/>
</form>

<?php
if(trim($_POST['password'])!=trim($_POST['repassword'])){
 exit('兩次密碼不一致，請(qǐng)返回上一頁');
} 
 //$_POST用戶名和密碼
 $username = $_POST['username'];
 $password = $_POST['password'];
 //連接mysql
 $con = mysqli_connect('localhost','root','');
 //驗(yàn)證mysql連接是否成功
if(mysqli_errno($con)){
 echo "連接mysql失?。?.mysqli_error($con);
 exit;
}
//設(shè)置數(shù)據(jù)庫字符集
 mysqli_set_charset($con,'utf8');
 //查看數(shù)據(jù)庫emp
 mysqli_select_db($con,'emp');
 //查看表sgbf用戶名與密碼和傳輸值是否相等
 $sql = "select *from sgbf where username='$username' and password='$password'";
 //result必需規(guī)定由 mysqli_query()、mysqli_store_result() 或 mysqli_use_result() 返回的結(jié)果集標(biāo)識(shí)符。
 $result = mysqli_query($conn,$sql);
 $num = mysqli_num_rows($result);// 函數(shù)返回結(jié)果集中行的數(shù)量
 if($num){
 
 echo '成功';
 }else{
 echo'失敗';
 }
 mysqli_close($con);
 ?>