Edit in JSFiddle

Result
HTML
<html>
<head>
    <script src="http://mbostock.github.com/d3/d3.v2.js?2.8.1"></script>
    <script src="https://rawgithub.com/stepheneb/netlogo-gcc/master/lib/simple-graph.js"></script>
    <script>
var graph = null,
    dataSet = [],
    tempFormatter = d3.format("2.1f");

$(function() {
    graph = simpleGraph()
        .title("Arduino Temperature Graph")
        .xmax(100).ymax(35)
        .xLabel("Time")
        .yLabel("Temperature");

    d3.select("#graph").call(graph);
    $('#run-button').click(function() {
        setInterval(getData, 250);
        $('#run-button').html("Running...")
            .attr("disabled", true)
            .unbind();        
    });
});

function getData() {
    $.getJSON("http://169.254.1.1/&callback=?", arduinoEthernetComCallback);
}

function arduinoEthernetComCallback(jsonData) {
    var a0 = JSON.parse(jsonData).A0,
        temperatureC = ((a0 * 5.0) / 1024.0) * 100;
    $("#currTemp").html(tempFormatter(temperatureC) + "&deg;C");
    dataSet.push(temperatureC);
    graph.set_data(dataSet);
};
</script>
</head>
<body>
    <button id="run-button">Start Reading</button>
  <div id="graph">
  </div>
  <div class="reading-box">
    The current temperature is <span id="currTemp">&mdash;</span>&deg;C
  </div>
</body>
</html>