$(document).ready(function(){
   
    $('#search_submit').click(function(){
        var model  = $("select[name='model'] :selected").val(); 
        var price  = $("select[name='price'] :selected").val(); 
        var year  = $("select[name='year'] :selected").val(); 
        var month  = $("select[name='month'] :selected").val(); 
        var milage  = $("select[name='milage'] :selected").val(); 
        if(model=='none' && price=='none' && year=='none' && month=='none' && milage=='none'){
           jAlert('請最少選擇一種搜尋類別，謝謝!','訊息視窗');
        }else if(year!='none' && month=='none' || year=='none' && month!='none'){
           jAlert('當你選擇「年份」時，請同時也選擇「月份」!','訊息視窗');
        }else{
           document.form_search.submit();
        } 
    });
});