I have been racking my brains attempting to sort this out however it does not appear to assist. I am by using this wordpress plugin http://www.viadat.com/store-locator/ and ive added a custom form area that is category.. However i wish to have the ability to search via that custom form area.

Below may be the code:

$form="
<div id='sl_div'>
<form onsubmit='searchLocations(); return false;' id='searchForm' action=''>
    <div class='left_map_sidebar'>
 ";

if (get_option('sl_use_city_search')!=1) {$form.=" colspan='2' ";}

$form.="               <input type='text' class='postcode' value='Enter Post Code' id='addressInput' size='50' />

";



 /*if ($cs_array && get_option('sl_use_city_search')==1) {
 $form.="
 <td id='addressInput2_container'>";
 $form.="<select Class='city' id='addressInput2'       onchange='aI=document.getElementById(\"searchForm\").addressInput;if(this.value!=\"\"){oldvalue=aI.value;aI.value=this.value;}else{aI.value=oldvalue;}'>
     <option value=''>--Search By City--</option>$cs_options</select></td>";
}*/



if ($category_array && get_option('sl_use_category_search')==1) {
$form.="
<td id='addressInput2_container'>";
$form.="<select Class='city'>
    <option value=''>--Search By Category--</option>$category_options</select></td>";
}


/*if ($name_array && get_option('sl_use_name_search')==1) {
    $form.="<td valign='top'><nobr>&nbsp;<b>OR</b>&nbsp;</nobr></td>";
}

if ($name_array && get_option('sl_use_name_search')==1) {
$form.="
<td valign='top'>";
$form.="<select id='addressInput3' onchange='aI=document.getElementById(\"searchForm\").addressInput;if(this.value!=\"\"){oldvalue=aI.value;aI.value=this.value;}else{aI.value=oldvalue;}'>
    <option value=''>--Search By Name--</option>
    $name_options
      </select>";

$form.="<input name='addressInput3'><input type='hidden' value='1'    name='name_search'></td>";
}*/



$sl_radius_label=get_option('sl_radius_label');
$form.="
</tr><tr>
 ".__("$sl_radius_label", $text_domain)."<br/>
 <td id='radiusSelect_td' ";

if (get_option('sl_use_city_search')==0) {$form.="colspan='2'";}

$form.="><select id='radiusSelect'>$r_options</select>
</td>
<td valign='top' ";

if (get_option('sl_use_city_search')!=0) {$form.="colspan='2'";}

$form.=" >
    <td valign='top' ";

if (get_option('sl_use_category_search')!=1) {$form.="colspan='3'";}

$form.=" >
    <input type='submit' class='search_map_button' value='Search Locations' id='addressSubmit'/> </td>
'</div>'

    <tr id='cm_mapTR'>
    <td width='' valign='top' style='/*display:hidden; border-right:solid silver 1px*/' id='map_sidebar_td'> <div id='map_sidebar' style='width:$width$width_units;/* $height$height_units; */'> <div class='text_below_map'>$sl_instruction_message</div></div>
    </td></tr>