javascript - 滚动时设置类的背景颜色，并且类必须在固定位置

我需要在滚动时更改 class(backwhitemarq) 的背景颜色，并且 class backwhitemarq 必须固定位置吗？

html 代码:

<div class="backwhitemarq">
 /*i need to change the background color for this class.*/
 <center> offer of the day</center>
</div>

css 代码:

.backwhitemarq
{
   background-color: #f6e454;
   padding: 3px;
   border-radius: 3px;
   height: 44px;
   margin-top: 15px;
   position:fixed;   //fixed
   width:100%;
   z-index:100;
}
.spacewww     /*another class for background color*/
{
   background-color:green;
}

javascript 代码:

<script type="text/javascript">
$(window).scroll(function()   /*scroll function for window*/
 {
     var speedscr =$('backwhitemarq'),
     scroll = $(window).scrollTop();

     if (scroll >= 10)
     {
        speedscr.addClass("spacewww");
     } else
     {
        speedscr.removeClass("spacewww");
    }
 });
 </script>

最佳答案

$(window).scroll(function()   /*scroll function for window*/
 {
  var speedscr =$('.backwhitemarq');
     var scroll = $(window).scrollTop();

    if (scroll >= 10)
    {
       speedscr.addClass("spacewww");
    } else
    {
        speedscr.removeClass("spacewww");
    }
 });

body{ height: 10000px; }
  .backwhitemarq
{
background-color: #f6e454;
padding: 3px;
border-radius: 3px;
height: 44px;
margin-top: 15px;
position:fixed;   //fixed
width:100%;
z-index:100;
}
.spacewww     /*another class for background color*/
{
background-color:green;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="backwhitemarq">/*i need to change the background color for this class.*/
 <center> offer of the day</center>
  </div>

我想你忘了在 jquery 选择器中添加 .(dot)

<script type="text/javascript">
$(window).scroll(function()   /*scroll function for window*/
 {
  var speedscr =$('.backwhitemarq'),
     scroll = $(window).scrollTop();

    if (scroll >= 10)
    {
       speedscr.addClass("spacewww");
    } else
    {
        speedscr.removeClass("spacewww");
    }
 });
  </script>

关于javascript - 滚动时设置类的背景颜色，并且类必须在固定位置，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/39178474/