function clearSearch(){
    document.search_form.style.options.selectedIndex = 0;
    document.search_form.layout.options.selectedIndex = 0;
    document.search_form.building_area.options.selectedIndex = 0;
    document.search_form.land_area.options.selectedIndex = 0;
    document.search_form.area.options.selectedIndex = 0;
    
    document.search_form.submit();
}