保留GET中的选中值

i have the codes that retain the value after post back. i also want to retain the value using GET. example i have ( example.php?id) i want to retain the value using $_GET['id'] what method should i do .

 if(isset($_POST) && isset($_POST['sym1']) && in_array($condition1,$_POST['sym1']))
            $strIsChecked='checked="checked"';
        else
            $strIsChecked=null;

                 echo '<br><input type="checkbox" '.$strIsChecked.' title ="'.$otherspec1.'" name="sym1[]"  onclick="javascript: submit()" value ="'.$condition1.'">';   echo ''.$condition1.'</td>';

Is this what you need?

// this is suppose to replace your If(...)..  
$sym1 = isset($_REQUEST["sym1"]) ? $_REQUEST["sym1"] : '';
$strIsChecked = in_array($sym1, array('option1', 'option2')) ? 'checked="checked"' : null;
echo '<br><input type="checkbox" '.$strIsChecked.' title ="'.$otherspec1.'" name="sym1[]"  onclick="javascript: submit()" value ="'.$condition1.'">';
echo ''.$condition1.'</td>';

// your code with modification  .....
if(isset($_REQUEST) && isset($_REQUEST['sym1']) && in_array($condition1,$_POST['sym1']))
    $strIsChecked='checked="checked"';
else
    $strIsChecked=null;

echo '<br><input type="checkbox" '.$strIsChecked.' title ="'.$otherspec1.'" name="sym1[]"  onclick="javascript: submit()" value ="'.$condition1.'">';   echo ''.$condition1.'</td>';