固定背景实现的背景滚动特效示例分享_javascript技巧

/* Set all parents to full height */ 
html, body, 
.container, 
.cbp-fbscroller, 
.cbp-fbscroller section { 
height: 100%; 
} 
/* The nav is fixed on the right side and we center it by translating it 50% 
(we don't know it's height so we can't use the negative margin trick) */ 
.cbp-fbscroller > nav { 
position: fixed; 
z-index: 9999; 
right: 100px; 
top: 50%; 
-webkit-transform: translateY(-50%); 
-moz-transform: translateY(-50%); 
-ms-transform: translateY(-50%); 
transform: translateY(-50%); 
} 
.cbp-fbscroller > nav a { 
display: block; 
position: relative; 
color: transparent; 
height: 50px; 
} 
.cbp-fbscroller > nav a:after { 
content: ''; 
position: absolute; 
width: 24px; 
height: 24px; 
border-radius: 50%; 
border: 4px solid #fff; 
} 
.cbp-fbscroller > nav a:hover:after { 
background: rgba(255,255,255,0.6); 
} 
.cbp-fbscroller > nav a.cbp-fbcurrent:after { 
background: #fff; 
} 
/* background-attachment does the trick */ 
.cbp-fbscroller section { 
position: relative; 
background-position: top center; 
background-repeat: no-repeat; 
background-size: cover; 
background-attachment: fixed; 
} 
#fbsection1 { 
background-image: url(../images/1.jpg); 
} 
#fbsection2 { 
background-image: url(../images/2.jpg); 
} 
#fbsection3 { 
background-image: url(../images/3.jpg); 
} 
#fbsection4 { 
background-image: url(../images/4.jpg); 
} 
#fbsection5 { 
background-image: url(../images/5.jpg); 
}

/** 
* cbpFixedScrollLayout.js v1.0.0 
* http://www.codrops.com 
* 
* Licensed under the MIT license. 
* http://www.opensource.org/licenses/mit-license.php 
* 
* Copyright 2013, Codrops 
* http://www.codrops.com 
*/ 
var cbpFixedScrollLayout = (function() { 
// cache and initialize some values 
var config = { 
// the cbp-fbscroller′s sections 
$sections : $( '#cbp-fbscroller > section' ), 
// the navigation links 
$navlinks : $( '#cbp-fbscroller > nav:first > a' ), 
// index of current link / section 
currentLink : 0, 
// the body element 
$body : $( 'html, body' ), 
// the body animation speed 
animspeed : 650, 
// the body animation easing (jquery easing) 
animeasing : 'easeInOutExpo' 
}; 
function init() { 
// click on a navigation link: the body is scrolled to the position of the respective section 
config.$navlinks.on( 'click', function() { 
scrollAnim( config.$sections.eq( $( this ).index() ).offset().top ); 
return false; 
} ); 
// 2 waypoints defined: 
// First one when we scroll down: the current navigation link gets updated. 
// A `new section′ is reached when it occupies more than 70% of the viewport 
// Second one when we scroll up: the current navigation link gets updated. 
// A `new section′ is reached when it occupies more than 70% of the viewport 
config.$sections.waypoint( function( direction ) { 
if( direction === 'down' ) { changeNav( $( this ) ); } 
}, { offset: '30%' } ).waypoint( function( direction ) { 
if( direction === 'up' ) { changeNav( $( this ) ); } 
}, { offset: '-30%' } ); 
// on window resize: the body is scrolled to the position of the current section 
$( window ).on( 'debouncedresize', function() { 
scrollAnim( config.$sections.eq( config.currentLink ).offset().top ); 
} ); 
} 
// update the current navigation link 
function changeNav( $section ) { 
config.$navlinks.eq( config.currentLink ).removeClass( 'cbp-fbcurrent' ); 
config.currentLink = $section.index( 'section' ); 
config.$navlinks.eq( config.currentLink ).addClass( 'cbp-fbcurrent' ); 
} 
// function to scroll / animate the body 
function scrollAnim( top ) { 
config.$body.stop().animate( { scrollTop : top }, config.animspeed, config.animeasing ); 
} 
return { init : init }; 
})();