如果用户获得else语句，是否可以刷新页面或禁用下一个文本字段？

 <?php
    require_once("dbcon.php");

    if(!empty($_POST["username"])) {

    $result = mysql_query("SELECT count(*) FROM users WHERE userName='" . 

    $_POST["username"] . "'");

    $row = mysql_fetch_row($result);
    $user_count = $row[0];

      if($user_count>0) {

          echo "<span class='status-not-available'> Username registered</span>";

      }else{
          echo "<span class='status-available'> Username not Available.</span>"; 
   }

   }

?>

this is my code thank you!

<?php
require_once("dbcon.php");

if(!empty($_POST["username"])) {

$result = mysql_query("SELECT count(*) FROM users WHERE userName='" . 

$_POST["username"] . "'");

$row = mysql_fetch_row($result);
$user_count = $row[0];

  if($user_count>0) {
      die("{success:true, message: \"Username registered.\"}");

  }else{
      die("{success:true, message: \"Username not Available.\"}");
   }

   }

?>

Then you can catch the success value to define your textfield

Edit: put this to your js :

var Stat = form.reader.jsonData.Message;

This 'Stat' will gives you themessage