console 命令行工具 X clear

console

      var svg = d3.select("body").append('svg')
       .attr('width',100)
       .attr('height',100)

       svg.append('circle')
          .attr('cx',50)
          .attr('cy',50)
          .attr("r", 10)
          .attr('fill',"red")

<html> 
  <head> 
      <meta charset="utf-8"> 
      <script src="https://d3js.org/d3.v5.min.js"></script>
  </head> 
    <body> 
        <p></p>
        <p></p>
    </body> 
</html>