区分移动端和pc端:
window.navigator.userAgent.toLowerCase().indexOf(\'mobile\')== -1 判断 等于-1就是pc,false就是移动端。
mouseenter和mouseleave 防止了嵌套的触发;
if(window.navigator.userAgent.toLowerCase().indexOf(\'mobile\')==-1){
$(\'.dropdown\').bind(\'mouseenter\',function(){
$(this).parent().siblings().find(\'.dropdown\').removeClass(\' open\');
$(this).addClass(\' open\');
}).bind(\'mouseleave\',function(){
$(this).removeClass(\' open\');
})