title: How to change the onClick function of C3 load function
body: <p>I am trying to update a C3 graph with different onclick funtion by using the load function of C3.</p>
  
  <p>The code snippet is here: </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>var json1 = [{
              date: '2014-01-01',
              upload: 200,
              download: 200,
              total: 400
          }, {
              date: '2014-01-02',
              upload: 100,
              download: 300,
              total: 400
          }, {
              date: '2014-02-01',
              upload: 300,
              download: 200,
              total: 500
          }, {
              date: '2014-02-02',
              upload: 400,
              download: 100,
              total: 500
          }];
          
          var json2 = [{
              date: '2014-01-01',
              upload: 200,
              download: 500,
              total: 700
          }, {
              date: '2014-01-02',
              upload: 500,
              download: 450,
              total: 950
          }, {
              date: '2014-02-01',
              upload: 200,
              download: 800,
              total: 1000
          }, {
              date: '2014-02-02',
              upload: 300,
              download: 500,
              total: 800
          }];
          
  var chart = c3.generate({
     bindto: '#div1',  
    data: {
          json: json1,
          onclick: function (event) {
           console.log("11111111111") ;               
      },
          keys: {
              x: 'date',
              value: ['upload', 'download']
          }
      },
      axis: {
          x: {
              type: 'timeseries',
              tick: {
                  format: function (x) {
                      if (x.getDate() === 1) {
                          return x.toLocaleDateString();
                      }
                  }
              }
          }
      }
  });
  
  setTimeout(function () {
      chart.unload();
  }, 1000);
  
  setTimeout(function () {
      chart.load({
                  json: json2,
                  keys: {
                      x: 'date',
                      value: ['upload', 'download']
                  },
                  onclick: function (event) {
                console.log("22222222") ;               
                  },
              });
  }, 1000);</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;link href="https://rawgit.com/masayuki0812/c3/master/c3.css" rel="stylesheet"/&gt;
  &lt;script src="https://rawgit.com/masayuki0812/c3/master/c3.js"&gt;&lt;/script&gt;
  &lt;script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.10/d3.min.js"&gt;&lt;/script&gt;
  &lt;div id="div1"&gt;&lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>Please tell me a way so to update the onClick funtion on the load function itself.</p>