从阿贾克斯到爪哇脚本的返回值

Question

我正在尝试检查数据库中是否已存在名称。但是我的Ajax没有返回值，老实说，甚至不确定Ajax是否正在运行。这是我在php页面上的代码。<input class="form-control" id="name" name="name" onblur="checkNameStatus()" /><script>        function checkNameStatus(){    //alert('Start of funtion');    var name=$("#name").val();    //alert("Name Input value is: "+name);    $.ajax({        type:'post',            url:'<?php echo base_url() ?>assets/ajax/checkName.php?name='+name,            success:function(msg){            alert(msg);                 }     });     //alert("End of function");    }</script>使用警报，我可以判断该函数确实正在运行并接收名称输入的值。然后是我的阿贾克斯<?php$hostname   = 'localhost';$username   = 'root';$password   = '123';$dbname     = 'test_db';function clean($string) {   return preg_replace('/[^A-Za-z0-9\- .!@#$%&]/', '', $string);}$name= clean($_GET['name']);$msg = "";$conn=mysqli_connect($hostname,$username,$password,$dbname);if (mysqli_connect_errno()){    echo ("Failed to connect to MySQL: " . mysqli_connect_error());}$sql = "SELECT * FROM pattern where name = '$name';";$check=mysqli_query($conn, $sql);$count=mysqli_num_rows($check);if($count!=0)   {     $msg = "A Schedule Pattern with the Name of $name already exists. If you continue to use this Name it will overwrite $name's current Data.";     return $msg;   } else {    $msg = "Count check Failed";     echo $msg;   }mysqli_close($con); ?>如何从我的ajax接收$msg变量并将其返回到脚本，然后随后在警报中显示它？

Answer 1

我认为你必须改变这一点

$check=mysql_query($sql);

$count=mysql_num_rows($check);

对此

$check=mysqli_query($conn, $sql);

$count=mysqli_num_rows($check);

您正在同时使用mysql_和mysqli_这是错误的，这可能是它未能检查计数的原因，我还建议您在找不到名称的情况下发送错误消息。

编辑，完整代码应为：（菲律宾比索）：

<?php

$hostname   = 'localhost';

$username   = 'root';

$password   = '123';

$dbname     = 'test_db';

function clean($string) {

   return preg_replace('/[^A-Za-z0-9\- .!@#$%&]/', '', $string);

}

if(isset($_GET['name'])){

$name= clean($_GET['name']);

$msg = "";

$conn=mysqli_connect($hostname,$username,$password,$dbname);

if (mysqli_connect_errno()){

    echo ("Failed to connect to MySQL: " . mysqli_connect_error());

}

$sql = "SELECT * FROM pattern where `name` = '$name';";

$check=mysqli_query($conn, $sql);

$count=mysqli_num_rows($check);

if($count!=0)

   {

     $msg = "A Schedule Pattern with the Name of $name already exists. If you continue to use this Name it will overwrite $name's current Data.";

     echo $msg;

   } else {

    $msg = "Count check Failed"; 

    echo $msg;

   }    

mysqli_close($conn);   

}  

?>