使用PHP Msqli进行ajax实时搜索，无需重新加载页面

Question

当用户在文本框中搜索其获取数据但页面已重新加载时。 我想要当用户搜索数据加载而不重新加载或刷新页面时 我在一页Ajax.php中编写代码。

这是我的代码，无法进行实时搜索 呼叫Ajax并像这样查询

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script src="jquery-3.4.1.min.js"></script>

js：

    $(document).ready(function () {
$('#Search-btn').click(function(){
        var searchtxt =$('#search').val();

        if($.term(searchtxt)!= ''){
            $.ajax({
                url="ajax.php",
                method:"POST",
                data:{search:searchtxt},

                success:function(data)
                {
                    $('#search').val();
                }
            });

        }
    });
    setInterval(function() {
        $('#here').load("ajax.php").fadeIn("slow");
    }, 1000);
});  
    </script>

这是我的PHP代码

    <form >
<div style="width:100%;height:80px;">
<h3 style="float: left;"> Student Who Have Exames In The Same Day</h3>
<div style="text-align:right;">
<input type="text"id="search" name="search" style="height:25px;border-radius: 25px;margin:40px;">
<input type="submit"class="hide" id="Search-btn"name="btn"value="Search">
</div>
</form> 
<div id="here"style="width:100%;height:80px;border:3px solid red;" >
    <?php
$connection = mysqli_connect("localhost", "FEP", "FEP", "FEP", '8889');
$test='CREATE TEMPORARY table search 
SELECT `Class_ID`,`Subject_ID`,Examdata.`Student_ID`,`Subject_name`,`exam_days`,Examdata.`exam_dates`,`exam_times` from Examdata join (SELECT Student_ID, count(*), exam_dates FROM Examdata group by Student_ID, exam_dates having count(*) > 1) Examdata1 on Examdata.Student_ID=Examdata1.Student_ID and Examdata1.exam_dates=Examdata.exam_dates order by Examdata1.Student_ID,Examdata1.exam_dates';
$t=mysqli_query($connection,$test);
$out="";
if(isset($_POST["search"]) && isset($_POST["btn"] )) {
    $srq=$_POST["search"];

    $ser="SELECT * FROM search  where
     Class_ID like  '%$srq%'    or Subject_ID like   '%$srq%'
     or Student_ID like  '%$srq%'   or Subject_name like   '%$srq%'   or exam_days like   '%$srq%'    or
     exam_dates like  '%$srq%'  or exam_times like   '%$srq%' ";
    $qr=mysqli_query($connection,$ser)or die("Error in query: $qr. " . mysqli_error());
    $count=mysqli_num_rows($qr);
    if($count == 0){
        $out="no";
    }
    else{
        while($ro=mysqli_fetch_array($qr)){
            echo '<td> Student ID: ' . $ro["Student_ID"] . '</td></tr>';
            echo '<tr style="display:none;">';
            echo '<td class="">' . $ro["Class_ID"] . '</td>';
            echo '<td class="">' . $ro["Subject_ID"] . '</td>';
            echo '<td class="">' . $ro["Subject_name"] . '</td>';
            echo '<td class="">' . $ro["exam_days"] . '</td>';
            echo '<td class="">' . $ro["exam_dates"] . '</td>';
            echo '<td class="">' . $ro["exam_times"] . '</td></tr>';

        }
    }
}
echo $out;