javascript 在 jQuery 中获取滚轮数量
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Get scroll wheel amount in jQuery
提问by tskuzzy
After binding the scroll event to an object, how can I get the amount the user scrolled by?
将滚动事件绑定到对象后，如何获取用户滚动的量？
$(selector).scroll(function(e) {
// get scroll amount
});
Firefox and Opera have the property detailwhereas IE, Safari, and Opera have wheelData. To make matters worse, Firefox and Opera operate on a scale of -3 to 3, and IE and Safari go from -120 to 120.
Firefox 和 Opera 具有该属性，detail而 IE、Safari 和 Opera 具有wheelData. 更糟糕的是，Firefox 和 Opera 的评分范围为 -3 到 3，而 IE 和 Safari 的评分范围为 -120 到 120。
Is there a single, normalized property that jQuery provides for this?
jQuery 是否为此提供了一个单一的、规范化的属性？
回答by snies
Use jQuery .scrollTop()and save the value between scroll events, then get the delta at next scroll event.
使用 jQuery .scrollTop()并保存滚动事件之间的值，然后在下一个滚动事件中获取增量。
var old_scroll_top = 0;
$(document).scroll(function() {
var current_scroll_top = $(document).scrollTop();
var scroll_delta = current_scroll_top - old_scroll_top;
// do something with current_scroll_top and scroll_delta
old_scroll_top = current_scroll_top;
});
Example:jsFiddle
示例：jsFiddle
Update:
更新：
Hereis a second Example, which shows how to have a canvas, that updates according to scoll Events.
这是第二个示例，它展示了如何拥有一个根据 scoll 事件更新的画布。
回答by ply
Could you use scrollTop for this?
您可以为此使用 scrollTop 吗？
var amount = $(window).scrollTop();
