问文本框在分页中消失- php

EN

 <body>
    <form name="myform" class="wrapper">
      <input type="text" name="q"  onkeyup="showPage();" class="txt_search"/>
      <input type="button" name="button" onclick="showPage();" class="button"/>
      <p>
        <div id="txtHint"></div>
        <div id="page"></div>

    </form>
  </body>

$self = $_SERVER['PHP_SELF'];
            $limit = 5; //Number of results per page
            $numpages=ceil($totalrows/$limit);

            $query = $query." ORDER BY idQuotes LIMIT " . ($page-1)*$limit . ",$limit";
            $result = mysql_query($query, $conn)
             or die('Error:' .mysql_error());
?>

<div class="caption">Search Results</div>
<div class="center_div">
<table>
    <?php while ($row= mysql_fetch_array($result, MYSQL_ASSOC)) {
        $cQuote =  highlightWords(htmlspecialchars($row['cQuotes']), $search_result);
        ?>
        <tr>
        <td style="text-align:right; font-size:15px;"><?php h($row['cArabic']); ?></td>
            <td style="font-size:16px;"><?php echo $cQuote; ?></td>
            <td style="font-size:12px;"><?php h($row['vAuthor']); ?></td>
            <td style="font-size:12px; font-style:italic; text-align:right;"><?php h($row['vReference']); ?></td>
        </tr>
    <?php } ?>
</table>
</div>

<?php
   //Create and print the Navigation bar
       $nav="";
       if($page > 1) {
            $nav .= "<a href=\"$self?page=" . ($page-1) . "&q=" .urlencode($search_result) . "\">< Prev</a>";

            $first = "<a href=\"$self?page=1&q=" .urlencode($search_result) . "\"><< First</a>" ;
        }

        else {
            $nav .= "&nbsp;";
            $first = "&nbsp;";
        }

       for($i = 1 ; $i <= $numpages ; $i++) {
            if($i == $page) {
                $nav .= "<B>$i</B>";
            }else{
                $nav .= "<a href=\"$self?page=" . $i . "&q=" .urlencode($search_result) . "\">$i</a>";
            }
        }

        if($page < $numpages) {
            $nav .= "<a href=\"$self?page=" . ($page+1) . "&q=" .urlencode($search_result) . "\">Next ></a>";

            $last = "<a href=\"$self?page=$numpages&q=" .urlencode($search_result) . "\">Last >></a> ";
        }

        else {

             $nav .= "&nbsp;";
             $last = "&nbsp;";
        }

        echo "<br /><br />" . $first . $nav . $last;


    }

var xmlHttp

function showPage(str)
{
    var str = document.myform.q.value;

xmlHttp=GetXmlHttpObject();
if (xmlHttp==null)
 {
 alert ("Browser does not support HTTP Request");
 return;
 }

var url="search.php";
url += "?q="+str+"&list=";
url += "&sid="+Math.random();
xmlHttp.onreadystatechange=stateChanged;
xmlHttp.open("GET",url,true);
xmlHttp.send(null);
}


function stateChanged(){
if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete"){
document.getElementById("txtHint").innerHTML=xmlHttp.responseText;
} //end if
} //end function

function GetXmlHttpObject() {
var xmlHttp=null;
try {
// For these browsers: Firefox, Opera 8.0+, Safari
xmlHttp=new XMLHttpRequest();
}catch (e){
//For Internet Explorer
try{
xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
}
}
return xmlHttp;
} //end function */