D3.JS rendered list node, how to display only the parent node, the child node needs to be clicked to show - Codes Helper

style of instance
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">

    <title>Tree Example</title>

    <style>

    .node {
        cursor: pointer;
    }

    .node circle {
        stroke: "-sharpf0f";
        stroke-width: 4px;
    }

    .node text {
      font: 12px sans-serif;
    }

    .link {
      fill: none;
      stroke: -sharpccc;
      stroke-width: 2px;
    }
  .fill_normal {
    fill: green;
  }
  .bling{ animation: alarm 0.4s  ease-in  infinite ; fill:yellow; font-weight: bold;}
  @keyframes alarm {
      0%{ fill:-sharpFF9966;}
      50%{ fill:-sharpFF3333;}
      100%{ fill:-sharpFF9966;}
  }

    </style>

  </head>

  <body>

<!-- load the d3.js library -->
<script src="http://d3js.org/d3.v3.min.js"></script>

<script>

var treeData = [
  {
    "name": "Top Level",
    "parent": "null",
    "value": 10,
    "children": [
      {
        "name": "Level 2: A",
        "parent": "Top Level",
        "value": 10,
        "children": [
          {
            "name": "Son of A",
            "parent": "Level 2: A",
            "value": 5
          },
          {
            "name": "Daughter of A",
            "parent": "Level 2: A",
            "value": 5
          },
        ]
      },
      {
        "name": "Level 2: B",
        "parent": "Top Level",
        "value": 5
      },
      {
        "name": "Level 2: C",
        "parent": "Top Level",
        "value": 5
      },
    ]
  }
];
// ************** Generate the tree diagram  *****************
//
var margin = {top: 20, right: 120, bottom: 20, left: 120},
    width = 960 - margin.right - margin.left,
    height = 500 - margin.top - margin.bottom;

var i = 0,
    duration = 750,//
    root;

var tree = d3.layout.tree()//
    .size([height, width]);

var diagonal = d3.svg.diagonal()
    .projection(function(d) { return [d.y, d.x]; });//

//
var svg = d3.select("body").append("svg")
    .attr("width", width + margin.right + margin.left)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

root = treeData[0];//treeData
root.x0 = height / 2;
root.y0 = 0;

update(root);

d3.select(self.frameElement).style("height", "500px");

function update(source) {

  // Compute the new tree layout.
  var nodes = tree.nodes(root).reverse(),
      links = tree.links(nodes);

  // Normalize for fixed-depth.y180px
  nodes.forEach(function(d) { d.y = d.depth * 180; });

  // Update the nodesnodegroup
  var node = svg.selectAll("g.node")
      .data(nodes, function(d) { return d.id || (d.id = PPi); });//data():

  // Enter any new nodes at the parent"s previous position.
  var nodeEnter = node.enter().append("g")  // svg gg svg  group  lines  rects circles 
      .attr("class", "node") //attrhtmlstylecss
      .attr("transform", function(d) { return "translate(" + source.y0 + "," + source.x0 + ")"; })
      .on("click", click);
  //---
  // nodeEnter.append("circle")
    //   .attr("r", 1e-6);//d 

  nodeEnter.append("path")
    .style("stroke-width", "2px")
    .style("stroke", "-sharp4682b4")
    .style("fill", "white")
    .attr("d", d3.svg.symbol()
                 .size(function(d){ if
                    (d.value <= 9) { return "400"; } else if
                    (d.value >= 9) { return "400";}
                  })
                 .type(function(d) { if
                    (d.value <= 9) { return "triangle-up"; } else if
                    (d.value >= 9) { return "circle";}
                  }))
    .attr("class",function(d){
      if(d.value <= 9 ){
        return "bling";
      }else{
        return "fill_normal";
      }
    });

  //
  nodeEnter.append("text")
      .attr("x", function(d) { return d.children || d._children ? -13 : 13; })
      .attr("dy", ".35em")
      .attr("text-anchor", function(d) { return d.children || d._children ? "end" : "start"; })
      .text(function(d) { return d.name; })
      .style("fill-opacity", 1e-6);

  // Transition nodes to their new position.-----
  //node
  var nodeUpdate = node.transition()  //
      .duration(duration)  //,
      .attr("r", 10)
    .attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; });
  //
  // nodeUpdate.select("circle")
  // .attr("r", 10)
  // .attr("class",function(d){
  //   if(d.value <= 9){
  //     return "bling";
  //   }else{
  //     return "fill_normal";
  //   }
  // });
  
  nodeUpdate.select("path")
    .style("stroke-width", "2px")
    .style("stroke", "-sharp4682b4")
    .style("fill", "white")
    .attr("d", d3.svg.symbol()
                 .size(function(d){ if
                    (d.value <= 9) { return "400"; } else if
                    (d.value >= 9) { return "400";}
                  })
                 .type(function(d) { if
                    (d.value <= 9) { return "triangle-up"; } else if
                    (d.value >= 9) { return "circle";}
                  }))
    .attr("class",function(d){
      if(d.value <= 9 ){
        return "bling";
      }else{
        return "fill_normal";
      }
    });

  nodeUpdate.select("text")
      .style("fill-opacity", 1);

  // Transition exiting nodes to the parent"s new position.
  //
  var nodeExit = node.exit().transition()
      .duration(duration)
      .attr("transform", function(d) { return "translate(" + source.y + "," + source.x + ")"; })
      .remove();

  nodeExit.select("circle")
      .attr("r", 1e-6);

  nodeExit.select("text")
      .style("fill-opacity", 1e-6);

  // Update the links
  //
  var link = svg.selectAll("path.link")
      .data(links, function(d) { return d.target.id; });

  // Enter any new links at the parent"s previous position.
  //
  link.enter().insert("path", "g")
      .attr("class", "link")
      .attr("d", function(d) {
        var o = {x: source.x0, y: source.y0};
        return diagonal({source: o, target: o});  //diagonal - , .
      })
    .style("stroke",function(d){
      //dconsole.log(d)
      return "-sharpccc";
    });

  // Transition links to their new position.
  //
  link.transition()
      .duration(duration)
      .attr("d", diagonal);

  // Transition exiting nodes to the parent"s new position.
  //
  link.exit().transition()
      .duration(duration)
      .attr("d", function(d) {
        var o = {x: source.x, y: source.y};
        return diagonal({source: o, target: o});
      })
      .remove();

  // Stash the old positions for transition.
  nodes.forEach(function(d) {
    d.x0 = d.x;
    d.y0 = d.y;
  });
}

//
// Toggle children on click.
function click(d) {
  if (d.children) {
    d._children = d.children;
    d.children = null;
  } else {
    d.children = d._children;
    d._children = null;
  }
  update(d);
}

</script>
  
  </body>
</html>