使用jQuery更改数据滚动速度？

Question

我使用下面的代码来改变某些元素的滚动速度。我从HERE复制的代码。

要仔细检查我的整体的代码，我还增加了一个颜色变化来“.slogan-A线”。

的如果/其他取决于如果“＃图像-UL”是充分上述浏览器窗口的底部边缘。

我的问题是，当调整窗口大小或滚动浏览器窗口时，“.slogan-a-line”的颜色确实会改变，但其他元素的数据滚动速度不会。他们在什么时候（重新）加载。

最初，当第一加载网页时，正确的数据滚动速度是由码集。但调整浏览器窗口时 - 要改变“＃图像-UL”是否完全上面的浏览器窗口的底部边缘或不可─数据滚动的速度不会改变，直到我刷新网页（所以id和类名正确）。

我所需要的数据滚动速度来改变，而无需刷新浏览器窗口。任何人都可以看到我做错了什么？

<script> 
    // Assign attribute specific "data-scroll-speed" to elements upon loading, resizing and scrolling of the webpage page. "if/else" is depending on if #image-ul is fully above the bottom edge of the browser window. 
    $(document).ready(function() { 
    $(window).on('load resize scroll', function() { 
     var WindowScrollTop = $(this).scrollTop(), 
     Div_one_top = $('#image-ul').offset().top, 
     Div_one_height = $('#image-ul').outerHeight(true), 
     Window_height = $(this).outerHeight(true); 
     if (WindowScrollTop + Window_height >= (Div_one_top + Div_one_height)) { 
     $('#sloganenglish').attr('data-scroll-speed', '2'); 
     $('.slow-scroll-slider').attr('data-scroll-speed', '5'); 
     $('.slogan-a-line').css('color', 'green'); 
     } else { 
     $('#sloganenglish').attr('data-scroll-speed', '1'); 
     $('.slow-scroll-slider').attr('data-scroll-speed', '1'); 
     $('.slogan-a-line').css('color', 'red'); 
     } 
    }).scroll(); 
    }); 


    // data-scroll-speed script 
    $.fn.moveIt = function() { 
    var $window = $(window); 
    var instances = []; 

    $(this).each(function() { 
     instances.push(new moveItItem($(this))); 
    }); 

    window.onscroll = function() { 
     var scrollTop = $window.scrollTop(); 
     instances.forEach(function(inst) { 
     inst.update(scrollTop); 
     }); 
    } 
    } 

    var moveItItem = function(el) { 
    this.el = $(el); 
    this.speed = parseInt(this.el.attr('data-scroll-speed')); 
    }; 

    moveItItem.prototype.update = function(scrollTop) { 
    var pos = scrollTop/this.speed; 
    this.el.css('transform', 'translateY(' + -pos + 'px)'); 
    }; 

    // Initialization 
    $(function() { 
    $('[data-scroll-speed]').moveIt(); 
    }); 
</script> 

Answer 1

查看答案EXAMPLE HERE！

// 
// default speed ist the lowest valid scroll speed. 
// 
var default_speed = 1; 
// 
// speed increments defines the increase/decrease of the acceleration 
// between current scroll speed and data-scroll-speed 
// 
var speed_increment = 0.01; 
// 
// maximum scroll speed of the elements 
// 
var data_scroll_speed_a = 4; // #sloganenglish 
var data_scroll_speed_b = 5; // .slogan-a-line 
// 
// 
// 
var increase_speed, decrease_speed, target_speed, current_speed, speed_increments; 
$(document).ready(function() { 
    $(window).on('load resize scroll', function() { 
     var WindowScrollTop = $(this).scrollTop(), 
      Div_one_top = $('#image-ul').offset().top, 
      Div_one_height = $('#image-ul').outerHeight(true), 
      Window_height = $(this).outerHeight(true); 
     if (WindowScrollTop + Window_height >= (Div_one_top + Div_one_height)) { 
      $('#sloganenglish').attr('data-scroll-speed', data_scroll_speed_a).attr('data-current-scroll-speed', default_speed).attr('data-speed-increments', data_scroll_speed_a * speed_increment); 
      $('.slogan-a-line').attr('data-scroll-speed', data_scroll_speed_b).attr('data-current-scroll-speed', default_speed).attr('data-speed-increments', data_scroll_speed_b * speed_increment); 
      $('.slogan-a-line').css('color', 'yellow'); 
      increase_speed = true; 
      decrease_speed = false; 
     } else { 
      $('#sloganenglish').attr('data-scroll-speed', '1').attr('data-current-scroll-speed', default_speed); 
      $('.slogan-a-line').attr('data-scroll-speed', '1').attr('data-current-scroll-speed', default_speed); 
      $('.slogan-a-line').css('color', 'red'); 
      decrease_speed = true; 
      increase_speed = false; 
     } 
    }).scroll(); 
}); 


// data-scroll-speed script 
$.fn.moveIt = function() { 
    var $window = $(window); 
    var instances = []; 

    $(this).each(function() { 
     instances.push(new moveItItem($(this))); 
    }); 

    window.onscroll = function() { 
     var scrollTop = $window.scrollTop(); 
     instances.forEach(function(inst) { 
      inst.update(scrollTop); 
     }); 
    } 
} 

var moveItItem = function(el) { 
    this.el = $(el); 
    this.speed = parseInt(this.el.attr('data-scroll-speed')); 
    this.current_speed = 1.0; 
}; 

moveItItem.prototype.update = function(scrollTop) { 

    target_speed = parseInt(this.el.attr('data-scroll-speed')); 
    current_speed = this.current_speed; 
    speed_increments = parseFloat(this.el.attr('data-speed-increments')); 

    if(increase_speed){ 
     if(current_speed < target_speed){ 
       current_speed += speed_increments; 
     } else { 
      current_speed = target_speed; 
     } 
    } else if(decrease_speed){ 
     if(current_speed > default_speed){ 
      current_speed -= speed_increments; 
     } 
     if($(window).scrollTop() === 0){ 
      current_speed = default_speed; 
     } 
    } 
    this.current_speed = current_speed; 
    var pos = scrollTop/this.current_speed; 
    this.el.css('transform', 'translateY(' + -pos + 'px)'); 
}; 

// Initialization 
$(function() { 
    $('[data-scroll-speed]').moveIt(); 
});