使用分页

Question

<form>
<select id="name" >
    <option></option>
    <option>Варна</option>
    <option>Бургас</option>
    <option>София</option>
    <option>Благоевград</option>
    </select>
    <input type="button" name="RememberMe" onclick="post();">
    </form>
    <script>function post()
        {
     //alert("working");
         var name = $('#name').val();
          var type = $('#type').val();
         var raion = $('#raion').val();



          $.post('post.php',{postgrad:name,posttype:type,postraion:raion},
             function(data){
          $('#result').html(data);
          });
            }
      <?php
      // the php
      <?php


                <?php


         $name = $_POST['postgrad'];
         $type = $_POST['posttype'];
         $raion =$_POST['postraion'];



        $conn = mysqli_connect('localhost','root','','seacapit_webhelper');
        mysqli_set_charset($conn, "utf8");

        // find out how many rows are in the table 
        $sql = "SELECT COUNT(*) FROM products";
        $result = mysqli_query($conn,$sql);
        $r = mysqli_fetch_row($result);
        $numrows = $r[0];

        // number of rows to show per page
        $rowsperpage = 10;
        // find out total pages
        $totalpages = ceil($numrows / $rowsperpage);

        // get the current page or set a default
        if (isset($_GET['currentpage']) && is_numeric($_GET['currentpage'])) 
         {
           // cast var as int
           $currentpage = (int) $_GET['currentpage'];
        } else {
           // default page num
           $currentpage = 1;
        } // end if

        // if current page is greater than total pages...
        if ($currentpage > $totalpages) {
           // set current page to last page
           $currentpage = $totalpages;
        } // end if
        // if current page is less than first page...
        if ($currentpage < 1) {
           // set current page to first page
           $currentpage = 1;
        } // end if

        // the offset of the list, based on current page 
        $offset = ($currentpage - 1) * $rowsperpage;

        // get the info from the db 


        $query = "SELECT * FROM products  join pic on products.pr_short_name 
        = pic.pr_short_name where products.search_txt1 = '".$name."'LIMIT 
         $offset, $rowsperpage";
        $result = mysqli_query($conn, $query);


            while($row = mysqli_fetch_assoc($result))
            {
                $pr_name = $row['pr_name'];
                $search_txt1 = $row['search_txt1'];
                $search_txt2 = $row['search_txt2'];
                $picture = $row['pic_file'];
                $search_txt3 = $row['search_txt3'];

                echo

                "<div class='container' >
            <div class='row'>
                <div class='col-md-5'>
                   <img width='100' src='".$picture."'/> 
                </div>
                <div class='col-md-7'>" .$pr_name  .  
                "</div>
                    <div class='col-md-4' ><p class='text-center'>" . 
               $search_txt1 . "</p> </div>
                        <div class='col-md-4' ><p class='text-center'>" . 
                $search_txt2 . "</p> </div>
                    <div class='col-md-4' ><p class='text-center'>" . 
              $search_txt3 . "</p> </div>
            </div>
        </div> ";
            }

         // end while

        /******  build the pagination links ******/
        // range of num links to show
        $range = 3;

        // if not on page 1, don't show back links
        if ($currentpage > 1) {
           // show << link to go back to page 1
           echo " <a href='index.php?currentpage=1'><<</a> ";
           // get previous page num
           $prevpage = $currentpage - 1;
           // show < link to go back to 1 page
           echo " <a href='index.php?currentpage=$prevpage'><</a> ";
        } // end if 

        // loop to show links to range of pages around current page
        for ($x = ($currentpage - $range); $x < (($currentpage + $range) + 
        1); $x++) {
           // if it's a valid page number...
           if (($x > 0) && ($x <= $totalpages)) {
              // if we're on current page...
              if ($x == $currentpage) {
                 // 'highlight' it but don't make a link
                 echo " [<b>$x</b>] ";
              // if not current page...
              } else {
                 // make it a link
                 echo " <a href='index.php?currentpage=$x'>$x</a> ";
              } // end else
           } // end if 
        } // end for

        // if not on last page, show forward and last page links        
        if ($currentpage != $totalpages) {
           // get next page
           $nextpage = $currentpage + 1;
            // echo forward link for next page 
           echo " <a href='index.php?currentpage=$nextpage'>></a> ";
           // echo forward link for lastpage
           echo " <a href='index.php?currentpage=$totalpages'>>></a> ";
        } // end if
        /****** end build pagination links ******/
        ?>

尝试代码时的问题是： 单击提交时有效，但当我使用分页尝试下一页时，$ _POST ['postname']不再被识别未定义索引：postname 。你能给我一个例子，说明如何使用$ _SESSION或cookie来存储$ _POST。 感谢当时的任何人