Gene Visualization Updated

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
  </style>
</head>

<body>
  <script>
    // Feel free to change or delete any of the code you see in this editor!
    var svg = d3.select("body").append("svg")
      .attr("width", 960)
      .attr("height", 500)

d3.json("data.json", function(err, mydata) 
     {d3.select("svg").selectAll("rect")
       var rectGroup = d3.select("svg").selectAll("g")
   			.data(mydata)
      	.enter()
       	.append("g")
      	.attr("transform", function (d) 
          {if (d.orientation == "forward") 
          {return "translate(" + -(d.stop - d.start) + ", 150)";}
        	else if (d.orientation == "reverse") 
          {return "translate(960 , 250)";}})
      rectGroup.transition()
      .duration(1000)
      .delay(function (d) {return d.start})
       	.attr("transform", function (d) 
          {if (d.orientation == "forward") 
          {return "translate(" + d.start + ", 150)";}
        	else if (d.orientation == "reverse") 
          {return "translate(" + d.start + ", 250)";}})
       rectGroup.append("rect")
      	.attr("height", 50)
      	.attr("width", function (d) 
         	{return d.stop - d.start;})
      	.attr("fill", function(d) 
          {if (d.orientation == "forward") 
          {return "green";}
        	else if (d.orientation == "reverse") 
          {return "red";}})
       	.attr("stroke", "black")
       	.attr("stroke-width", 3)
    	 rectGroup.append("text")
         .text(function (d) {return d.name})
       		.attr("x", function (d) {return (d.stop - d.start)/2})
       		.attr("y", 25)
       		.attr("text-anchor", "middle")
       		.attr("alignment-baseline", "central")
   				.style("fill", "black")
     })
  		
       
       
      	
  </script>
</body>

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