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>