fps, timer, svg 960 lines

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>timer / fps</title>
  <script src="//d3js.org/d3.v4.min.js"></script>
</head>
<body>
  <div id="fps">FPS: <span>?</span></div>
</body>
  
<script>
var w = 960, h = 100;

var svg = d3.select("body")
            .append("svg")
              .attr("width",w)
              .attr("height",h);

var data = d3.range(w).map(function(d,i) {
  return {
    x1: i,
    y1: 0,
    x2: i,
    y2: Math.trunc(Math.random()*h)
  };  
});

var fps = d3.select("#fps span");

var t0 = Date.now(), t1;

d3.timer( function() {
  
  data.forEach( function(d) {
    d.y2++;
    if (d.y2 > h) d.y2 = 0; 
  })
  lines.attr("y2", function(d) {return d.y2;} )
  
  t1 = Date.now();
  fps.text( Math.round(1000 / (t1-t0)));
  t0 = t1;
  
});

</script>

</html>

https://d3js.org/d3.v4.min.js