$_GET变量在分页代码中未定义

我不熟悉PHP，我遇到了一个为期两周的问题，关于如何在分页代码中生成$_GET或$_SESSION变量。情况是：

我有一个来自index.php页面的值，当我点击它时（例如照片/图像），我会使用get获得该值，然后当我将该值回显到Category.php页面时，该值会使用"echo"在BODY页面中正常投影，但我想要的是，当页面加载时，get变量将是我分页代码中的搜索键。但是，当我在分页代码中回显GET变量时，我得到的结果是"UNDEFINED"，这意味着该变量没有在分页代码内定义。这是我的页码。哦，是的，我对我的代码做了更改，我很抱歉，但这是我使用$mycat和GET方法的前一个代码。对不起。

<?php
session_start();
$mycat =$_GET['category'];
//PHP code for specific search
$action = (isset($_REQUEST['action'])&& $_REQUEST['action'] !=NULL)?$_REQUEST['action']:'';
if($action == 'ajax'){
    /* Connect To Database*/
    $dbname = 'ufile';
    $link = mysql_connect("localhost","root","") or die("Couldn't make connection.");
    $db = mysql_select_db($dbname, $link) or die("Couldn't select database");
    $mycat =  htmlspecialchars ($_GET['category']) ? trim($_GET['category']) : ''; //SQL injection protection
    include 'pagination.php'; //include pagination file
    //pagination variables
    $page = (isset($_REQUEST['page']) && !empty($_REQUEST['page']))?$_REQUEST['page']:1;
    $per_page = 10; //how many records you want to show
    $adjacents  = 4; //gap between pages after number of adjacents
    $offset = ($page - 1) * $per_page;
    echo 'Result: ' .$mycat; //////////THIS IS THE GET VALUE....WHICH TURNS OUT AS UNDEFINED IN VALUE IT SHOULD BE 'PHOTOS/IMAGES, AUDIOS/VIDEOS or COMPRESSED FILES'....PLEASE HELP ME.
    //Count the total number of row in your table*/
    $count_query   = mysql_query("SELECT COUNT(category) AS numrows FROM udocs WHERE category LIKE '%" . $mycat . "%'"); //Count the number of search result here (tagal kitang hinanap dito ka lng pala)
    $row     = mysql_fetch_array($count_query);
    $numrows = $row['numrows'];
    $total_pages = ceil($numrows/$per_page);
    $reload = 'cat_index.php';
    //main query to fetch the data
    $result = mysql_query("SELECT * FROM udocs WHERE category LIKE '%" . $mycat . "%' ORDER BY date_upload LIMIT $offset,$per_page");

    //loop through fetched data
    while($test = mysql_fetch_array($result)){
        $id = $test['file_name'];   
            $fileid=$test['file_path'];
            echo "<div class='content'>";
                echo'<div class="img_content"  ><img src='.$test['file_icon'].' style=height:50px;width:50px;float:left;margin-right:10px;></div>';
                echo"<font  color='black'; font size='2px !important' ;font family='Century Gothic, sans-serif' ;letter spacing='2px';>Name:   </font><font color='yellowgreen'; font size='2px !important' ;font family='Century Gothic, sans-serif' ;letter spacing='2px';>" .$test['file_name']."</font><br>";
                    echo"<font color='black'; font size='2px !important' ;font family='Century Gothic, sans-serif' ;letter spacing='2px';>Category:   </font><font color='gray'; font size='2px !important' ;font family='Century Gothic, sans-serif' ;letter spacing='2px';>" .$test['category']."</font></font><font color='skyblue'; font size='2px !important' ;font family='Century Gothic, sans-serif' ;letter spacing='2px';>   |   </font><font color='black'; font size='2px !important' ;font family='Century Gothic, sans-serif' ;letter spacing='2px';>Size:   </font><font color='gray'; font size='2px !important' ;font family='Century Gothic, sans-serif' ;letter spacing='2px';>" .$test['file_size']."</font></font><font color='skyblue'; font size='2px !important' ;font family='Century Gothic, sans-serif' ;letter spacing='2px';>   |   </font><font color='black'; font size='2px !important' ;font family='Century Gothic, sans-serif' ;letter spacing='2px';>Credits to:   </font><font color='gray'; font size='2px !important' ;font family='Century Gothic, sans-serif' ;letter spacing='2px';>" .$test['author']."</font><font color='skyblue'; font size='2px !important' ;font family='Century Gothic, sans-serif' ;letter spacing='2px';>   |   </font><font color='black'; font size='2px !important' ;font family='Century Gothic, sans-serif' ;letter spacing='2px';>Date Uploaded:   </font><font color='gray'; font size='2px !important' ;font family='Century Gothic, sans-serif' ;letter spacing='2px';>" .$test['date_upload']."</font><br>";
                    echo"<font color='black'; font size='2px !important' ;>Description:". $test['description']. "</font><br>";
                    echo"<a href ='download.php?file_path=$fileid' ><font color='orange' title='$mycat'>Download File</p></a>";
            echo        "</div>";
}
    //BOTTOM
    if ($numrows==0)
    {
    }
    else
    {
        echo paginate($reload, $page, $total_pages, $adjacents);
    }
    //header('Location:index.php');
    //die();
} // end of ajax first condition
else
{
?>
<body>
<?php
 echo 'You are searching for: '.$mycat;
?>
</body>
<?php } ?>