为什么我的画布菜单打开时把固定的div从框架中推出来？

Question

我使用精力充沛的画布菜单为我的网站，它的工作很好，但它麻烦我的固定div头。当我向下滚动页面，标题完美地贴在顶部，但一旦我打开画布菜单，我的标题消失？当我关闭我的画布菜单时，它突然回来了。看起来怪怪的。

您可以检查(代码笔) 这里是我问题的现场演示。或直接运行下面的代码段。

我希望它在打开画布菜单时保持可见。我会感谢你的帮助。

提前谢谢。

​

/*! Pushy - v1.0.0 - 2016-3-1
 * Pushy is a responsive off-canvas navigation menu using CSS transforms & transitions.
 * https://github.com/christophery/pushy/
 * by Christopher Yee */

(function($) {
  var pushy = $('.pushy'), //menu css class
    body = $('body'),
    container = $('#container'), //container css class
    push = $('.push'), //css class to add pushy capability
    pushyLeft = 'pushy-left', //css class for left menu position
    pushyOpenLeft = 'pushy-open-left', //css class when menu is open (left position)
    pushyOpenRight = 'pushy-open-right', //css class when menu is open (right position)
    siteOverlay = $('.site-overlay'), //site overlay
    menuBtn = $('.menu-btn, .pushy-link'), //css classes to toggle the menu
    menuSpeed = 200, //jQuery fallback menu speed
    menuWidth = pushy.width() + 'px', //jQuery fallback menu width
    submenuClass = '.pushy-submenu',
    submenuOpenClass = 'pushy-submenu-open',
    submenuClosedClass = 'pushy-submenu-closed',
    submenu = $(submenuClass);

  function togglePushy() {
    //add class to body based on menu position
    if (pushy.hasClass(pushyLeft)) {
      body.toggleClass(pushyOpenLeft);
    } else {
      body.toggleClass(pushyOpenRight);
    }
  }

  function openPushyFallback() {

    //animate menu position based on CSS class
    if (pushy.hasClass(pushyLeft)) {
      body.addClass(pushyOpenLeft);
      pushy.animate({
        left: "0px"
      }, menuSpeed);
      container.animate({
        left: menuWidth
      }, menuSpeed);
      //css class to add pushy capability
      push.animate({
        left: menuWidth
      }, menuSpeed);
    } else {
      body.addClass(pushyOpenRight);
      pushy.animate({
        right: '0px'
      }, menuSpeed);
      container.animate({
        right: menuWidth
      }, menuSpeed);
      push.animate({
        right: menuWidth
      }, menuSpeed);
    }

  }

  function closePushyFallback() {

    //animate menu position based on CSS class
    if (pushy.hasClass(pushyLeft)) {
      body.removeClass(pushyOpenLeft);
      pushy.animate({
        left: "-" + menuWidth
      }, menuSpeed);
      container.animate({
        left: "0px"
      }, menuSpeed);
      //css class to add pushy capability
      push.animate({
        left: "0px"
      }, menuSpeed);
    } else {
      body.removeClass(pushyOpenRight);
      pushy.animate({
        right: "-" + menuWidth
      }, menuSpeed);
      container.animate({
        right: "0px"
      }, menuSpeed);
      push.animate({
        right: "0px"
      }, menuSpeed);
    }

  }

  function toggleSubmenu() {
    //hide submenu by default
    $(submenuClass).addClass(submenuClosedClass);

    $(submenuClass).on('click', function() {
      var selected = $(this);

      if (selected.hasClass(submenuClosedClass)) {
        //hide opened submenus
        $(submenuClass).addClass(submenuClosedClass).removeClass(submenuOpenClass);
        //show submenu
        selected.removeClass(submenuClosedClass).addClass(submenuOpenClass);
      } else {
        //hide submenu
        selected.addClass(submenuClosedClass).removeClass(submenuOpenClass);
      }
    });
  }

  function toggleSubmenuFallback() {
    //hide submenu by default
    $(submenuClass).addClass(submenuClosedClass);

    submenu.children('a').on('click', function(event) {
      event.preventDefault();
      $(this).toggleClass(submenuOpenClass)
        .next('.pushy-submenu ul').slideToggle(200)
        .end().parent(submenuClass)
        .siblings(submenuClass).children('a')
        .removeClass(submenuOpenClass)
        .next('.pushy-submenu ul').slideUp(200);
    });
  }

  //checks if 3d transforms are supported removing the modernizr dependency
  var cssTransforms3d = (function csstransforms3d() {
    var el = document.createElement('p'),
      supported = false,
      transforms = {
        'webkitTransform': '-webkit-transform',
        'OTransform': '-o-transform',
        'msTransform': '-ms-transform',
        'MozTransform': '-moz-transform',
        'transform': 'transform'
      };

    // Add it to the body to get the computed style
    document.body.insertBefore(el, null);

    for (var t in transforms) {
      if (el.style[t] !== undefined) {
        el.style[t] = 'translate3d(1px,1px,1px)';
        supported = window.getComputedStyle(el).getPropertyValue(transforms[t]);
      }
    }

    document.body.removeChild(el);

    return (supported !== undefined && supported.length > 0 && supported !== "none");
  })();

  if (cssTransforms3d) {
    //make menu visible
    pushy.css({
      'visibility': 'visible'
    });

    //toggle submenu
    toggleSubmenu();

    //toggle menu
    menuBtn.on('click', function() {
      togglePushy();
    });
    //close menu when clicking site overlay
    siteOverlay.on('click', function() {
      togglePushy();
    });
  } else {
    //add css class to body
    body.addClass('no-csstransforms3d');

    //hide menu by default
    if (pushy.hasClass(pushyLeft)) {
      pushy.css({
        left: "-" + menuWidth
      });
    } else {
      pushy.css({
        right: "-" + menuWidth
      });
    }

    //make menu visible
    pushy.css({
      'visibility': 'visible'
    });
    //fixes IE scrollbar issue
    container.css({
      "overflow-x": "hidden"
    });

    //keep track of menu state (open/close)
    var opened = false;

    //toggle submenu
    toggleSubmenuFallback();

    //toggle menu
    menuBtn.on('click', function() {
      if (opened) {
        closePushyFallback();
        opened = false;
      } else {
        openPushyFallback();
        opened = true;
      }
    });

    //close menu when clicking site overlay
    siteOverlay.on('click', function() {
      if (opened) {
        closePushyFallback();
        opened = false;
      } else {
        openPushyFallback();
        opened = true;
      }
    });
  }
}(jQuery));

body {
  margin: 0px;
}
div.header {
  padding: 10px;
  box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19);
  position: fixed;
  top: 0;
  width: 100%;
  height: 40px;
  background: white;
  z-index: 100;
}
div.content {
  padding-top: 70px;
  padding-left: 300px;
  padding-right: 300px;
}
div.menu-btn {
  float: left;
  font-size: 20px;
}
/*! Pushy - v1.0.0 - 2016-3-1
* Pushy is a responsive off-canvas navigation menu using CSS transforms & transitions.
* https://github.com/christophery/pushy/
* by Christopher Yee */

/* Menu Appearance */

.pushy {
  position: fixed;
  width: 200px;
  height: 100%;
  top: 0;
  z-index: 9999;
  background: #191918;
  overflow: auto;
  visibility: hidden;
  -webkit-overflow-scrolling: touch;
  /* enables momentum scrolling in iOS overflow elements */
}
.pushy a {
  display: block;
  color: #b3b3b1;
  padding: 15px 30px;
  text-decoration: none;
  outline: 0;
}
.pushy a:hover {
  color: #FFF;
}
.pushy ul:first-child {
  margin-top: 10px;
}
.pushy.pushy-left {
  left: 0;
}
.pushy.pushy-right {
  right: 0;
}
/* Menu Movement */

.pushy-left {
  -webkit-transform: translate3d(-200px, 0, 0);
  -ms-transform: translate3d(-200px, 0, 0);
  transform: translate3d(-200px, 0, 0);
}
.pushy-open-left #container,
.pushy-open-left .push {
  -webkit-transform: translate3d(200px, 0, 0);
  -ms-transform: translate3d(200px, 0, 0);
  transform: translate3d(200px, 0, 0);
}
.pushy-right {
  -webkit-transform: translate3d(200px, 0, 0);
  -ms-transform: translate3d(200px, 0, 0);
  transform: translate3d(200px, 0, 0);
}
.pushy-open-right #container,
.pushy-open-right .push {
  -webkit-transform: translate3d(-200px, 0, 0);
  -ms-transform: translate3d(-200px, 0, 0);
  transform: translate3d(-200px, 0, 0);
}
.pushy-open-left .pushy,
.pushy-open-right .pushy {
  -webkit-transform: translate3d(0, 0, 0);
  -ms-transform: translate3d(0, 0, 0);
  transform: translate3d(0, 0, 0);
}
/* Menu Transitions */

#container,
.pushy,
.push {
  transition: transform 0.2s cubic-bezier(0.16, 0.68, 0.43, 0.99);
}
/* Site Overlay */

.site-overlay {
  display: none;
}
.pushy-open-left .site-overlay,
.pushy-open-right .site-overlay {
  display: block;
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 9998;
  background-color: rgba(0, 0, 0, 0.5);
  -webkit-animation: fade 500ms;
  animation: fade 500ms;
}
@keyframes fade {
  0% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}
@-webkit-keyframes fade {
  0% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}
/* Submenu Appearance */

.pushy-submenu {
  /* Submenu Icon */
}
.pushy-submenu ul {
  padding-left: 15px;
  transition: max-height 0.2s ease-in-out;
}
.pushy-submenu ul .pushy-link {
  transition: opacity 0.2s ease-in-out;
}
.pushy-submenu > a {
  position: relative;
}
.pushy-submenu > a::after {
  content: '';
  display: block;
  height: 11px;
  width: 8px;
  position: absolute;
  top: 50%;
  right: 15px;
  background: url("../img/arrow.svg") no-repeat;
  -webkit-transform: translateY(-50%);
  -ms-transform: translateY(-50%);
  transform: translateY(-50%);
  transition: transform 0.2s;
}
/* Submenu Movement */

.pushy-submenu-closed ul {
  max-height: 0;
  overflow: hidden;
}
.pushy-submenu-closed .pushy-link {
  opacity: 0;
}
.pushy-submenu-open {
  /* Submenu Icon */
}
.pushy-submenu-open ul {
  max-height: 1000px;
}
.pushy-submenu-open .pushy-link {
  opacity: 1;
}
.pushy-submenu-open a::after {
  -webkit-transform: translateY(-50%) rotate(90deg);
  -ms-transform: translateY(-50%) rotate(90deg);
  transform: translateY(-50%) rotate(90deg);
}
.no-csstransforms3d .pushy-submenu-closed ul {
  max-height: none;
  display: none;
}
/*# sourceMappingURL=pushy.css.map */

<!-- jQuery -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>


<body>
  <!-- Pushy Menu -->
  <nav class="pushy pushy-left">

  </nav>

  <!-- Site Overlay -->
  <div class="site-overlay"></div>

  <!-- Your Content -->
  <div id="container">
    <div class="header">
      <div class="menu-btn">&#9776; Sroll down a bit and Click me, I vanish (get stuck at top)</div>

    </div>


    <div align="center" class="content">
      <h1> Lorem Ipsum </h1>
      <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec quam felis, ultricies nec, pellentesque eu, pretium
        quis, sem. Nulla consequat massa quis enim. Donec pede justo, fringilla vel, aliquet nec, vulputate eget, arcu. In enim justo, rhoncus ut, imperdiet a, venenatis vitae, justo. Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras
        dapibus. Vivamus elementum semper nisi. Aenean vulputate eleifend tellus. Aenean leo ligula, porttitor eu, consequat vitae, eleifend ac, enim. Aliquam lorem ante, dapibus in, viverra quis, feugiat a, tellus. Phasellus viverra nulla ut metus varius
        laoreet. Quisque rutrum. Aenean imperdiet. Etiam ultricies nisi vel augue. Curabitur ullamcorper ultricies nisi. Nam eget dui. Etiam rhoncus. Maecenas tempus, tellus eget condimentum rhoncus, sem quam semper libero, sit amet adipiscing sem neque
        sed ipsum. Nam quam nunc, blandit vel, luctus pulvinar, hendrerit id, lorem. Maecenas nec odio et ante tincidunt tempus. Donec vitae sapien ut libero venenatis faucibus. Nullam quis ante. Etiam sit amet orci eget eros faucibus tincidunt. Duis
        leo. Sed fringilla mauris sit amet nibh. Donec sodales sagittis magna. Sed consequat, leo eget bibendum sodales, augue velit cursus nunc,</p>

      <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec quam felis, ultricies nec, pellentesque eu, pretium
        quis, sem. Nulla consequat massa quis enim. Donec pede justo, fringilla vel, aliquet nec, vulputate eget, arcu. In enim justo, rhoncus ut, imperdiet a, venenatis vitae, justo. Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras
        dapibus. Vivamus elementum semper nisi. Aenean vulputate eleifend tellus. Aenean leo ligula, porttitor eu, consequat vitae, eleifend ac, enim. Aliquam lorem ante, dapibus in, viverra quis, feugiat a, tellus. Phasellus viverra nulla ut metus varius
        laoreet. Quisque rutrum. Aenean imperdiet. Etiam ultricies nisi vel augue. Curabitur ullamcorper ultricies nisi. Nam eget dui. Etiam rhoncus. Maecenas tempus, tellus eget condimentum rhoncus, sem quam semper libero, sit amet adipiscing sem neque
        sed ipsum. Nam quam nunc, blandit vel, luctus pulvinar, hendrerit id, lorem. Maecenas nec odio et ante tincidunt tempus. Donec vitae sapien ut libero venenatis faucibus. Nullam quis ante. Etiam sit amet orci eget eros faucibus tincidunt. Duis
        leo. Sed fringilla mauris sit amet nibh. Donec sodales sagittis magna. Sed consequat, leo eget bibendum sodales, augue velit cursus nunc,</p>

      <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec quam felis, ultricies nec, pellentesque eu, pretium
        quis, sem. Nulla consequat massa quis enim. Donec pede justo, fringilla vel, aliquet nec, vulputate eget, arcu. In enim justo, rhoncus ut, imperdiet a, venenatis vitae, justo. Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras
        dapibus. Vivamus elementum semper nisi. Aenean vulputate eleifend tellus. Aenean leo ligula, porttitor eu, consequat vitae, eleifend ac, enim. Aliquam lorem ante, dapibus in, viverra quis, feugiat a, tellus. Phasellus viverra nulla ut metus varius
        laoreet. Quisque rutrum. Aenean imperdiet. Etiam ultricies nisi vel augue. Curabitur ullamcorper ultricies nisi. Nam eget dui. Etiam rhoncus. Maecenas tempus, tellus eget condimentum rhoncus, sem quam semper libero, sit amet adipiscing sem neque
        sed ipsum. Nam quam nunc, blandit vel, luctus pulvinar, hendrerit id, lorem. Maecenas nec odio et ante tincidunt tempus. Donec vitae sapien ut libero venenatis faucibus. Nullam quis ante. Etiam sit amet orci eget eros faucibus tincidunt. Duis
        leo. Sed fringilla mauris sit amet nibh. Donec sodales sagittis magna. Sed consequat, leo eget bibendum sodales, augue velit cursus nunc,</p>

      <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec quam felis, ultricies nec, pellentesque eu, pretium
        quis, sem. Nulla consequat massa quis enim. Donec pede justo, fringilla vel, aliquet nec, vulputate eget, arcu. In enim justo, rhoncus ut, imperdiet a, venenatis vitae, justo. Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras
        dapibus. Vivamus elementum semper nisi. Aenean vulputate eleifend tellus. Aenean leo ligula, porttitor eu, consequat vitae, eleifend ac, enim. Aliquam lorem ante, dapibus in, viverra quis, feugiat a, tellus. Phasellus viverra nulla ut metus varius
        laoreet. Quisque rutrum. Aenean imperdiet. Etiam ultricies nisi vel augue. Curabitur ullamcorper ultricies nisi. Nam eget dui. Etiam rhoncus. Maecenas tempus, tellus eget condimentum rhoncus, sem quam semper libero, sit amet adipiscing sem neque
        sed ipsum. Nam quam nunc, blandit vel, luctus pulvinar, hendrerit id, lorem. Maecenas nec odio et ante tincidunt tempus. Donec vitae sapien ut libero venenatis faucibus. Nullam quis ante. Etiam sit amet orci eget eros faucibus tincidunt. Duis
        leo. Sed fringilla mauris sit amet nibh. Donec sodales sagittis magna. Sed consequat, leo eget bibendum sodales, augue velit cursus nunc,</p>

      <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec quam felis, ultricies nec, pellentesque eu, pretium
        quis, sem. Nulla consequat massa quis enim. Donec pede justo, fringilla vel, aliquet nec, vulputate eget, arcu. In enim justo, rhoncus ut, imperdiet a, venenatis vitae, justo. Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras
        dapibus. Vivamus elementum semper nisi. Aenean vulputate eleifend tellus. Aenean leo ligula, porttitor eu, consequat vitae, eleifend ac, enim. Aliquam lorem ante, dapibus in, viverra quis, feugiat a, tellus. Phasellus viverra nulla ut metus varius
        laoreet. Quisque rutrum. Aenean imperdiet. Etiam ultricies nisi vel augue. Curabitur ullamcorper ultricies nisi. Nam eget dui. Etiam rhoncus. Maecenas tempus, tellus eget condimentum rhoncus, sem quam semper libero, sit amet adipiscing sem neque
        sed ipsum. Nam quam nunc, blandit vel, luctus pulvinar, hendrerit id, lorem. Maecenas nec odio et ante tincidunt tempus. Donec vitae sapien ut libero venenatis faucibus. Nullam quis ante. Etiam sit amet orci eget eros faucibus tincidunt. Duis
        leo. Sed fringilla mauris sit amet nibh. Donec sodales sagittis magna. Sed consequat, leo eget bibendum sodales, augue velit cursus nunc,</p>
    </div>
  </div>
</body>

</html>

​

Answer 1

关于这一点，有一个封闭的问题：

诀窍是在容器div之外有任何固定位置(如固定的标头)元素。有关示例，请参见demo.html。

在您的情况下，将.header移出#container是可行的。

如果您对造成这种情况的原因感兴趣，请参阅这个答案。