I have tried a code but it dosent work properly. Can you suggest a method to resolve the error. I am new to Visualization and at the beginning stage of d3.js
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="http://mbostock.github.com/d3/d3.js">    </script>
</head>
<body>
<div id="viz"></div>
<script type="text/javascript">
var sampleSVG = d3.select("#viz")
    .append("svg")
    .attr("width", 100)
    .attr("height", 100);    
sampleSVG.append("circle")
    .style("stroke", "gray")
    .style("fill", "white")
    .attr("r", 40)
    .attr("cx", 50)
    .attr("cy", 50)
    .on("mouseover", function()    {d3.select(this).append("text").attr("fill","blue").text("fill aliceblue");})
 </script>
 </body>
 </html>
 
     
     
    