Displaying some text on States on Map using D3.js and GeoJson

I have been working with Storm and Redis, and just to visualize the data am fetching from Redis, I need to render a map (India) and place the data according to the state. I have rendered the map correctly but just have no idea how to display the text within their respective state boundaries. Any help will be appreciated. Thanks.

<!DOCTYPE html>
<html lang="en">
<head>
<title>Visualization Demo</title>
<script type="text/javascript" src="d3.min.js"></script>
<script type="text/javascript" src="d3.geo.min.js"></script>

<link type="text/css" rel="stylesheet" href="color-scheme.css"/>
<style type="text/css">
svg {
    background: #282828;
}
body {
    background: #282828;
}
h1 {
    color:#999999;
}
#india {
    fill: #99FFCC;
    opacity: .9;
    stroke: white;
    stroke-width: 1.0;
}
#chart {
    margin-left:150px;
}
</style>
</head>

<body>
    <h1><center>VISUALIZATION</center></h1>
    <div id="chart"></div>
    <script type="text/javascript">
        var w = 1000;
        var h = 1500;
        var proj = d3.geo.mercator();
        var path = d3.geo.path().projection(proj);
        var t = proj.translate(); // the projection's default translation
        var s = proj.scale() // the projection's default scale
        var map = d3.select("#chart").append("svg:svg")
        .attr("width", w)
        .attr("height", h)
        .call(initialize);
        var india = map.append("svg:g")
        .attr("id", "india");
        d3.json("india-states.json", function (json) {
            india.selectAll("path")
            .data(json.features)
            .enter().append("path")
            .attr("d", path);
        });
        function initialize() {
            proj.scale(9000);
            proj.translate([-1520, 1000]);
        }
    </script>
</body>
</html>

Solution

Try this, inside your d3.json function:

india.selectAll("text")
    .data(json.features)
    .enter()
    .append("text")
    .attr("fill", "black")
    .attr("transform", function(d) { 
        var centroid = path.centroid(d);
        return "translate(" + centroid[0] + "," + centroid[1] + ")"
    })
    .attr("text-anchor", "middle")
    .attr("dy", ".35em")
    .text(function(d) {
          return d.properties.STATE_NAME;
    });

You probably don't have properties.STATE_NAME as the name of the states, but simply check in your JSON what you should use here.