how to highlight AJAX search result in a check box list without losing check box selections in php?

Question

I have a check box list of students and a search box in first php page .In ajax page I will get the search results .

But the problem is ,if user selected first search result and searched again selection on the first search is lost

How can I save selections on the first search ?I have tried to make selections in an session array but it is not working

//check list
    $qry="select cand_id,name from candidate where inst_id=".$_SESSION['inst_id']."";
    $res=$ob->select($qry,$connect);
    while($rw=pg_fetch_row($res))
    {

        echo"<br><input type=\"checkbox\" name=\"check[]\" value=\"$rw[0]\">";echo$rw[1];echo"<br>" ;
    }
//Ajax page
if($ajaxData!="")
{
                                if($_SESSION['usertype_id']==1)
                                {
                                $qry="select cand_id,name from candidate where name like'$dataup%'  ";

                                }
                                else if($_SESSION['usertype_id']==2)
                                {
                                $qry="select cand_id,name from candidate where inst_id=".$_SESSION['inst_id']."
                                and  name like'$dataup%' ";
                                }
                                $res=$ob->select($qry,$connect);
                                $words=array();
                                $count = pg_num_rows($res);
                                if($count>0)
                                {
                                    $i=0;
                                    //echo"<div  style=\"width: 200px; height: 200px;overflow-y: auto;padding-top: 10px;padding-right: 0px;padding-bottom: 0.25in;\">";
                                    while($rw=pg_fetch_row($res))
                                    {
                                        $words[$i]=$rw[0];$i++;


                                    }

                                    $_SESSION['checkAjax']=$words;//can_id array

1. How do I use array $_SESSION['checkAjax'] for highlighting?
2. Why $_SESSION['checkAjax'] unset on each ajax call?
3. Just need change of color on selected student names

Answer 1

I assume that you are having a code this way for the checkboxes:

<input type="checkbox" name="options[]" value="student"> Student
<input type="checkbox" name="options[]" value="teacher"> Teacher
<input type="checkbox" name="options[]" value="professor"> Professor

If this is the case, you can check it on server side this way, and I again assume it is by POST:

<input type="checkbox" name="options[]" value="student"<?php echo (in_array("student", $_POST["options"])) ? ' checked="checked"' : ''; ?>> Student
<input type="checkbox" name="options[]" value="teacher"<?php echo (in_array("teacher", $_POST["options"])) ? ' checked="checked"' : ''; ?>> Teacher
<input type="checkbox" name="options[]" value="professor"<?php echo (in_array("professor", $_POST["options"])) ? ' checked="checked"' : ''; ?>> Professor

Hope this helps! :)