javascript - 使用 HTML 和 CSS 修复滚动页面上的横幅

Question

<分区>

Answer 1

实例:http://jsfiddle.net/KXXhQ/

您需要使用 jQuery 的 scroll 事件，然后将一个新类添加到您的 header 以修复它:

jQuery

  //by default, the static menu is hidden
  var showStaticMenuBar = false;

  //when scrolling...
  $(window).scroll(function () {

      //if the static menu is not yet visible...
      if (showStaticMenuBar == false) {
          //if I scroll more than 200px, I show it 
          if ($(window).scrollTop() >= 200) {
              //showing the static menu
              $('#header').addClass('fixed');

              showStaticMenuBar = true;
          }
      }
      //if the static menu is already visible...
      else {
          if ($(window).scrollTop() < 200) {
              $('#header').removeClass('fixed');

              //I define it as hidden
              showStaticMenuBar = false;
          }
      }
  });

CSS

#header{
    display:block;
    width: 100%;
    height:50px;
    background: #ddff00;
}
#header.fixed{
    position:fixed; 
    top: 0;  /*fixing it at the top*/
    z-index: 999;  /* over any other element*/
}

实例:http://jsfiddle.net/KXXhQ/