$(document).ready(function(){
    if ($.browser.msie && $.browser.version < 7){
        $(".nav ul > li").mouseenter(function(){
            $(this).addClass('hover');
            if($(this).children('div.drop').length) $('.search-base select').css({visibility:'hidden'});
        }).mouseleave(function(){
            $(this).removeClass('hover');
            if($(this).children('div.drop').length) $('.search-base select').css({visibility:'visible'});
        });
    }
});