How to keep checkboxes checked and dropdown selections on submit

[jrpelt]

<input id="auction" type="checkbox" name="auction" value="Yes" /> 

When I submit a checkbox or dropdown the selections don't show. Would someone mind helping me, I'm sure it's simple I just don't know how to go about this.

 

[jrpelt]

this works to keep it checked but on first load I get the undefined index error.

<?php
// If the box was checked, keep it checked
    if ( isset($_POST['auction']) && $_POST['auction'] == 'Yes' ) {
         $checked = 'checked="checked"';
    } else {
         $checked = '';
    }
?>

<input id="auction" type="checkbox" name="auction" value="Yes" <?php echo $checked ?>/>

[jrpelt]

<?php
// If the box was checked, keep it checked
    if ( isset($_POST['auction']) && $_POST['auction'] == 'Yes' ) {
         $checked = 'checked="checked"';
    } else {
         $checked = '';
    }
?>

<input type="hidden" value="No" name="auction" /><!-- Added this to get rid of undefined index problem -->
<input id="auction" type="checkbox" name="auction" value="Yes" <?php echo $checked ?>/>

Okay so that took care of my undefined index problem and I now have a checkbox that remains checked after submitting the form. Now I want my drop down menus to retain their selected values.

[subhomoy]

you can also do it in this way...

 

<input id="auction" type="checkbox" name="auction" value="Yes" checked="checked"/>

[mac_gyver]

for drop-down select menus output selected="selected" inside the <option          > tag you want to be selected.