I have this class
.progress {
    width:200px;
    height:50px;
    border:1px solid black;
    position:relative;
}
.progress:after {
   position:absolute;
    background:black;
    top:0; bottom:0;
    left:0; 
    width:10%;
    -webkit-animation: filler 2s ease-in-out;
    -moz-animation: filler 2s ease-in-out;
    animation: filler 2s ease-in-out;
}
and have this div
<div id="percentDIV" class="progress" runat="server">some text</div>
I want to change width attribute of progress:after class in c# dynamically. Is it possible?
something like?
percentDIV.Attributes["class:progress:after"] = "width:25%";
 
     
    