D3 not displayed within jupyter notebook

Question

I am writing this html/javascript/d3 code within jupyter notebook, which runs without any error but it doesn't display anything. Ideally it should display two circles, one with color blue and other with color green. What could be an issue?

HTML('<script src="http://d3js.org/d3.v3.min.js"></script>')

HTML('''
<div class="legend">Sample</div>   
<div id="sample"></div>
 <script type="text/javascript">

 var svg=d3.select("#sample").append("svg").attr("width",500).attr("height",200);
 var dataset = [
{
    x: 10,
    y: 10,
    r: 2,
    text:"a",
    color:"blue"
},
{
    x: 20,
    y: 10,
    r: 2,
    text:"b",
    color:"green"
}];
 svg.selectAll("circle")
 .data(dataset)
 .enter()
 .append("circle")
 .attr("cx",function(d){return d.x;})
 .attr("cy",function(d){return d.y;})
 .attr("r",function(d){return d.r;})
 .attr("fill",function(d){return d.color;})
 .text(function(d){return d.text;});

 ''')

Answer 1

可能的问题：您忘记关闭<script type="text/javascript">谢谢！