JQuery窗口滾動頂部和底部

Question

我能夠加載我的ajax當滾動到底部時，我想弄清楚如何修改下面的代碼片段，以便它只在窗口滾動時才起作用到頂部？

$(window).scroll(function() { 
    if ($(document).height() <= $(window).scrollTop() + $(window).height()) { 
     //this works here for scrolling bottom 
    } 
    else if ($(document).height() >= $(window).scrollTop() + $(window).height()){ 

     //i tried checking for greater than the window scroll but that didn't owrk 
    } 
}); 

Answer 1

當scrollTop()返回滾動條的垂直位置就意味着滾動條處於頂部位置。

$(window).scroll(function() { 
    if ($(window).scrollTop() == 0){ 
     alert("Up"); 
    } 
}); 

或者，您可以按以下步驟更新您的代碼，

$(window).scroll(function() { 
    if ($(window).scrollTop() + $(window).height() < $(document).height()){ 
     alert("Up"); 
    //i tried checking for greater than the window scroll but that didn't work 
    } 
}); 

Answer 2

入住這或許你應該檢查一下文件和窗口對象的高度，以確保他們不爲空。

$(window).scroll(function() { 
      if ($(document).height() <= Number($(window).scrollTop() + $(window).height())) { 
       //this works here for scrolling bottom 
      } 
// only greater i think, not equa 
      else if ($(document).height() > Number($(window).scrollTop() + $(window).height())){ 

      } 
     });