title: how to highlight(change color) of all connected(neighbours) nodes and links in a d3 force directed graph
body: <p>I saw this example here 
  <a href="http://www.d3noob.org/2013/03/d3js-force-directed-graph-example-basic.html" rel="nofollow noreferrer">http://www.d3noob.org/2013/03/d3js-force-directed-graph-example-basic.html</a>
  I can understand it to an extent where I can make basic changes, but have not been able to do one thing specifically which is to highlight (change color) of all connected nodes. e.g If I mouse over node 1 or click on node 1,it should find all neighboring nodes and highlight the link paths by changing color.</p>
  
  <p>I looked at <a href="https://stackoverflow.com/questions/11206015/clicking-a-node-in-d3-from-a-button-outside-the-svg/11211391#11211391">clicking a node in d3 from a button outside the svg</a> already answered but I couldn't make it work on this example. </p>
  
  <p>I will be grateful if someone can help here and modify the existing code to achieve the searching of connected nodes/links.</p>
  
  <p>I do apologize if this is really a very basic question and I am missing something really obvious here.</p>