javascript - 上下滚动一个div

Question

我已经设置了一个 fiddle http://jsfiddle.net/austinind/aadcd/1/

我想要实现的是视差效果。

div 应该根据 scolling 上下滚动。

在我的例子中，div 只向上滚动:

 function parallax(){
var scrolled = $(window).scrollTop();
var elempos=$(".bg2").position().top;
$('.bg2').css('top', elempos-(scrolled * 0.2) + 'px');
}


$(window).scroll(function(e){
parallax();
 });

Answer 1

看看下面的Js fiddle

用于滚动的 Javascript

(function($) {

var types = ['DOMMouseScroll', 'mousewheel'];

if ($.event.fixHooks) {
    for ( var i=types.length; i; ) {
        $.event.fixHooks[ types[--i] ] = $.event.mouseHooks;
    }
}

$.event.special.mousewheel = {
    setup: function() {
        if ( this.addEventListener ) {
            for ( var i=types.length; i; ) {
                this.addEventListener( types[--i], handler, false );
            }
        } else {
            this.onmousewheel = handler;
        }
    },

    teardown: function() {
        if ( this.removeEventListener ) {
            for ( var i=types.length; i; ) {
                this.removeEventListener( types[--i], handler, false );
            }
        } else {
            this.onmousewheel = null;
        }
    }
};

$.fn.extend({
    mousewheel: function(fn) {
        return fn ? this.bind("mousewheel", fn) : this.trigger("mousewheel");
    },

    unmousewheel: function(fn) {
        return this.unbind("mousewheel", fn);
    }
});


function handler(event) {
    var orgEvent = event || window.event, args = [].slice.call( arguments, 1 ), delta = 0, returnValue = true, deltaX = 0, deltaY = 0;
    event = $.event.fix(orgEvent);
    event.type = "mousewheel";

    // Old school scrollwheel delta
    if ( orgEvent.wheelDelta ) { delta = orgEvent.wheelDelta/120; }
    if ( orgEvent.detail     ) { delta = -orgEvent.detail/3; }

    // New school multidimensional scroll (touchpads) deltas
    deltaY = delta;

    // Gecko
    if ( orgEvent.axis !== undefined && orgEvent.axis === orgEvent.HORIZONTAL_AXIS ) {
        deltaY = 0;
        deltaX = -1*delta;
    }

    // Webkit
    if ( orgEvent.wheelDeltaY !== undefined ) { deltaY = orgEvent.wheelDeltaY/120; }
    if ( orgEvent.wheelDeltaX !== undefined ) { deltaX = -1*orgEvent.wheelDeltaX/120; }

    // Add event and delta to the front of the arguments
    args.unshift(event, delta, deltaX, deltaY);

    return ($.event.dispatch || $.event.handle).apply(this, args);
}

})(jQuery);





// OUR CODE





var winH = $(window).height();
$('.page').height(winH);

var c = 0;
var pagesN = $('.page').length;


$(document).bind('mousewheel', function(ev, delta) {

    delta>0 ? --c : ++c ;    
    if(c===-1){
        c=0;
    }else if(c===pagesN){
        c=pagesN-1;
    }

    var pagePos = $('.page').eq(c).position().top;       
    $('html, body').stop().animate({scrollTop: pagePos},1000);
    return false; 

});