if ($(window).scrollTop() < 48) {
    $(".nav ").css("top", 48 - parseInt($(window).scrollTop()));
   }else{
    $(".nav ").css("top", "0"); 
   }
  $(window).scroll(function () {
   $(".nav ").css("top", "0");
   var toplength = parseInt($(window).scrollTop());
   if ($(window).scrollTop() < 48) {
    $(".nav ").css("top", 48 - toplength);
   }
 });

if ($(window).scrollTop() < 48) {
   $(".nav ").stop().animate({"top":48 - parseInt($(window).scrollTop())},"fast");
  } else {
   $(".nav ").stop().animate({"top": "0"},"fast");
  }
$(window).scroll(function () {
   var toplength = parseInt($(window).scrollTop());
   if ($(window).scrollTop() < 48) {
    $(".nav ").stop().animate({"top": 48 - toplength},"fast");
   }else{
   $(".nav ").stop().animate({"top": "0"},"fast"); 
   }
});

menuPosition: function() {
   var m = $(window).scrollTop(), 
   n = $("#idmenuinfo的父亲").offset().top,
   l = $("#menuinfo");
   if (m >= n) {
    if (!l.hasClass("menuinfo")) {
     l.addClass("menuinfo")
    }
   } else {
    l.removeClass("menuinfo")
   }
  }

.menuinfo {
 position: fixed!important;
 width: 100%;
 left: 0;
 top: 0;
}

$("body").on("touchstart", function(e) {
 e.preventDefault();
 startX = e.originalEvent.changedTouches[0].pageX,
 startY = e.originalEvent.changedTouches[0].pageY;
});
$("body").on("touchmove", function(e) {
 e.preventDefault();
 moveEndX = e.originalEvent.changedTouches[0].pageX,
 moveEndY = e.originalEvent.changedTouches[0].pageY,
 X = moveEndX - startX,
 Y = moveEndY - startY;

 if ( Math.abs(X) > Math.abs(Y) && X > 0 ) {
  alert("left 2 right");
 }
 else if ( Math.abs(X) > Math.abs(Y) && X < 0 ) {
  alert("right 2 left");
 }
 else if ( Math.abs(Y) > Math.abs(X) && Y > 0) {
  alert("top 2 bottom");
 }
 else if ( Math.abs(Y) > Math.abs(X) && Y < 0 ) {
  alert("bottom 2 top");
 }
 else{
  alert("just touch");
 }
});

 $('#haorooms底层背景').bind("touchmove", function (e) {
   e.preventDefault();
  });
  $(".滚动的父亲").bind("touchstart", function (events) {
   startY = events.originalEvent.changedTouches[0].pageY;
  });
  $(".滚动的父亲 ul").bind("touchmove", function (e) {
   var ulheight = $(this).height();
   var scrollTop = $(this).scrollTop();
   var scrollheight = $(this)[0].scrollHeight;
   if (ulheight + scrollTop + 20 >= scrollheight) { //滚到底部20px左右
    $(".滚动的父亲").bind("touchmove", function (event) {
     moveEndY = event.originalEvent.changedTouches[0].pageY,
       theY = moveEndY - startY;
     if (theY > 0) { //用上面的abs()更加准确！
      $(".滚动的父亲").unbind("touchmove");
     }
     if (theY < 0) {
      event.preventDefault();
     }
    })
   }
   if (scrollTop < 20) {//滚到顶部20px左右
    $(".滚动的父亲").bind("touchmove", function (event) {
     moveEndY = event.originalEvent.changedTouches[0].pageY,
       theY = moveEndY - startY;
     if (theY > 0) {
      event.preventDefault();
     }
     if (theY < 0) {
      $(".滚动的父亲").unbind("touchmove");
     }
    })
   }
  });