JS 获取滚动距离、滚动条高度，判断是否滚动到底部

原生JS实现

//滚动条滚动的距离：
 function getScrollTop(){var scrollTop = 0, bodyScrollTop = 0, documentScrollTop = 0;if(document.body) bodyScrollTop = document.body.scrollTop;if(document.documentElement) documentScrollTop = document.documentElement.scrollTop;scrollTop = (bodyScrollTop - documentScrollTop > 0) ? bodyScrollTop : documentScrollTop;return scrollTop;
 }
 //文档的总高度
 function getScrollHeight(){var scrollHeight = 0, bodyScrollHeight = 0, documentScrollHeight = 0;if(document.body) bodyScrollHeight = document.body.scrollHeight;if(document.documentElement) documentScrollHeight = document.documentElement.scrollHeight;scrollHeight = (bodyScrollHeight - documentScrollHeight > 0) ? bodyScrollHeight : documentScrollHeight;return scrollHeight;
 }
 //浏览器视口的高度，即滚动条高度
 function getWindowHeight(){var windowHeight = 0;if(document.compatMode == "CSS1Compat") windowHeight = document.documentElement.clientHeight;else windowHeight = document.body.clientHeight;return windowHeight;
 }function arriveBottom(){if(getScrollTop() + getWindowHeight() == getScrollHeight()) return true;else return false;
 };
 

JQuery实现

var scrollTop = $(this).scrollTop();
 var scrollHeight = $(document).height();
 var windowHeight = $(this).height();
 if(scrollTop + windowHeight == scrollHeight){alert("已经到最底部");
 }
 

红框是scrollTop，紫框是windowHeight，绿框是scrollHeight

参考：https://www.cnblogs.com/winyh/p/6715010.html