Question

下面的代码当前向下滚动div标签'navigation'（标题）到页面顶部，向上滚动时将其向下移动（在第二个标题下面）。我正在尝试调整它，以便每次向上滚动时都不会向下移动，但是当你到达页面顶部时。有谁知道我怎么能做到这一点？

// Move header on scroll down
var didScroll;
var lastScrollTop = 0;
var delta = 5;
var navbarHeight = $('.navigation').outerHeight();

$(window).scroll(function(event){
    didScroll = true;
});

setInterval(function() {
    if (didScroll) {
        hasScrolled();
        didScroll = false;
    }
}, 250);

function hasScrolled() {
    var st = $(this).scrollTop();

    // Make sure they scroll more than delta
    if(Math.abs(lastScrollTop - st) <= delta)
        return;

    // If they scrolled down and are past the navbar, add class .nav-up.
    if (st > lastScrollTop && st > navbarHeight){
        // Scroll Down
        $('.navigation').removeClass('.navigation').addClass('nav-up');
    } else {
        // Scroll Up
        if(st + $(window).height() < $(document).height()) {
            $('.navigation').removeClass('nav-up').addClass('.navigation');
        }
    }

    lastScrollTop = st;
}

Answer 1

$(window).scroll(function() {
   if($(window).scrollTop() == 0) { 
      // position menu for when unscrolled
   }
   else {
     // position menu for when scrolled
   }
});

这是一个类似于您尝试用来说明功能的应用程序：JSFIDDLE

当用户滚动到页面顶部时，如何才能使此代码仅显示div标签？

1 个答案: