Why doesn't my script load while adding d3plus.js chart?

Question

I am trying to add a chart to my website using d3plus.js. I get the following error message:

Uncaught TypeError: Cannot read property 'buttons' of null
    at SVGGElement.<anonymous> (d3plus.js:23745)
    at SVGGElement.__onmousemove (d3.js:1120)

I have tried placing the script to the beginning of the page and to after the footer too.

**head.php**
    <script src="../wp-content/themes/sage/bower_components/d3/d3.js"> </script>
    <script src="../wp-content/themes/sage/bower_components/d3plus/d3plus.js"></script>

**page.php**
    <div id="viz" width="1356" height="579"></div>

    <script>
    var data = [
      {"year": 1991, "name":"alpha", "value": 15},
      {"year": 1991, "name":"beta", "value": 10},
      {"year": 1991, "name":"gamma", "value": 5},
      {"year": 1991, "name":"delta", "value": 50},
      {"year": 1992, "name":"alpha", "value": 20},
      {"year": 1992, "name":"beta", "value": 10},
      {"year": 1992, "name":"gamma", "value": 10},
      {"year": 1992, "name":"delta", "value": 43},
      {"year": 1993, "name":"alpha", "value": 30},
      {"year": 1993, "name":"beta", "value": 40},
      {"year": 1993, "name":"gamma", "value": 20},
      {"year": 1993, "name":"delta", "value": 17},
      {"year": 1994, "name":"alpha", "value": 60},
      {"year": 1994, "name":"beta", "value": 60},
      {"year": 1994, "name":"gamma", "value": 25},
      {"year": 1994, "name":"delta", "value": 32}
    ]
    var visualization = d3plus.viz()
      .container("#viz")
      .data(data)
      .type("bar")
      .id("name")
      .height(300)
      .width(1100)
      .x("year")
      .y("value")
      .draw()
    </script>

On mouseover, the label should appear on the chart, but I get the error message:

Uncaught TypeError: Cannot read property 'buttons' of null
    at SVGGElement.<anonymous> (d3plus.js:23745)
    at SVGGElement.__onmousemove (d3.js:1120)

Answer 1

The problem was caused by not using the right version of the d3.js and the d3plus.js. I have downloaded the latest versions of the scripts and now I am able to add charts to my website:)