Scroll to top on click and change color after scrolling some length by jquery

//jquery used
$(window).scroll(function(){   
 var scrollval = $(window).scrollTop(); 
if(scrollval > 652) 
  {
   $(".scroller").css("color","white");
  }    if(scrollval < 652){
   $(".scroller").css("color","");
  }
  });
  $(".scroller").click(function(){
   $(window).scrollTop(0);
  });

//html used
<div class="scroller">
      Tap to scroll up
</div>
<div class="jtset">
        jtest
</div>

//css used
div .jtset{
      background:blue;
      height:500px;
      width:auto;
      padding:50px;
       }
div .scroller{
      background:;
      color:black;
      width:200px;
      position: fixed;
      top:300px;
      left: 10px;
     -ms-transform: rotate(270deg); /* IE 9 */
     -webkit-transform: rotate(270deg); /* Safari 3-8 */
      transform: rotate(270deg);
     }