<SVG>
  <circle fill="blue" cx="30" cy="30" r="30"></circle>
</SVG>
svg{
  height:100%;
  width:80%;
  border: 3px solid brown;
}
$(document).mousemove(sitioCirculo);

function sitioCirculo(e){
  
    $("svg>circle").css({"cx" : e.clientX });
    $("svg>circle").css({"cy": e.clientY });

}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js