function ajax_search() {
    var myAjax = new Ajax.Request(                    
        "/ajax_suche/",
        { 
            method: 'post',
            parameters: Form.serialize($('search_field')),
            onComplete: show_search_rslts
        }
    );
}

function show_search_rslts(originalRequest) {
   output_area = document.getElementById('ajax_search_output')               
   if (originalRequest.responseText.indexOf("RESULTS=NADA") == -1) {                                    
        switch_search_container('block')
        output_area.innerHTML = ""
        output_area.innerHTML = originalRequest.responseText                     
    }
    else {
        switch_search_container('none') 
    }
}            

function switch_search_container(state) {
    document.getElementById('ajax_search_output').style.display=state                
}