Multiple criteria trouble

i have script, this is the filter for jobboard. But I can select only job_type and view the results or job_pomer and view the results. Is there a way to display more than one select box, each one for a different taxonomy in order to filter posts by multiple criteria. I

Thank you

<?php
$taxonomy     = 'job_pomer';
$orderby      = 'name';
$show_count   = 1;      // 1 for yes, 0 for no
$pad_counts   = 0;      // 1 for yes, 0 for no
$hierarchical = 1;      // 1 for yes, 0 for no
$title        = '';

$arg = array(
  'taxonomy'     => $taxonomy,
  'orderby'      => $orderby,
  'show_count'   => $show_count,
  'hierarchical' => $hierarchical,
  'title_li'     => $title
);
?>

<ul>

</ul>

<h2><?php _e('Pomer práce:'); ?></h2>
<form id="categoriesform1" action="<?php bloginfo('url'); ?>" method="get">

<div>
<?php $cats = get_categories($arg); ?>
<select id="categories">
<?php foreach ($cats as $fat) : ?>
    <option value="<?php echo get_term_link($fat, $fat->taxonomy) ?>"><?php echo $fat->name ?></option>
<?php endforeach; ?>
</select>
<input type="submit" name="submit" value="view" />
</div>
</form>
<script>
jQuery(document).ready(function()
{
    jQuery('#categoriesform1').submit(function()
    {
        window.location = jQuery('#categories').val();
        return false;
    });
});
</script>

<?php
$taxonomy     = 'job_type';
$orderby      = 'name';
$show_count   = 1;      // 1 for yes, 0 for no
$pad_counts   = 0;      // 1 for yes, 0 for no
$hierarchical = 1;      // 1 for yes, 0 for no
$title        = '';

$args = array(
  'taxonomy'     => $taxonomy,
  'orderby'      => $orderby,
  'show_count'   => $show_count,
  'hierarchical' => $hierarchical,
  'title_li'     => $title
);
?>

<ul>

</ul>

<h2><?php _e('Typ práce:'); ?></h2>
<form id="categoriesform" action="<?php bloginfo('url'); ?>" method="get">

<div>
<?php $cats = get_categories($args); ?>
<select id="categories">
<?php foreach ($cats as $cat) : ?>
    <option value="<?php echo get_term_link($cat, $cat->taxonomy) ?>"><?php echo $cat->name ?></option>
<?php endforeach; ?>
</select>
<input type="submit" name="submit" value="view" />
</div>
</form>
<script>
jQuery(document).ready(function()
{
    jQuery('#categoriesform').submit(function()
    {
        window.location = jQuery('#categories').val();
        return false;
    });
});
</script>