I am using D3 for the first time and I have followed the instructions on their site to get to this point. I cannot seem to get the chart to display although there are no exceptions in the JS console in Chrome.

Here's the JS in the header of my page:

<script>
    var margin = {
    top: 0,
    right: 0,
    bottom: 10,
    left: 0
},
width = 838 - margin.left - margin.right,
    height = 300 - margin.top - margin.bottom;

var x = d3.scale.ordinal()
    .rangeRoundBands([0, width], .1);

var y = d3.scale.linear()
    .range([height, 0]);

var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom");

var yAxis = d3.svg.axis()
    .scale(y)
    .orient("left");

var chart = d3.select(".day_chart")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
    .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

d3.json(".php?var=TEST1&id=C120031", function (error, data) {

    data.forEach(function (d) {
        d.hour = +d.hour; // coerce to number
        d.max_energy = +d.max_energy;

        alert(d.hour + " -- " + d.max_energy);
    });

    x.domain(data.map(function (d) {
        return d.hour;
    }));
    y.domain([0, d3.max(data, function (d) {
        return d.max_energy;
    })]);

    chart.append("g")
        .attr("class", "x axis")
        .attr("transform", "translate(0," + height + ")")
        .call(xAxis);

    chart.append("g")
        .attr("class", "y axis")
        .call(yAxis);

    chart.selectAll(".bar")
        .data(data)
        .enter().append("rect")
        .attr("class", "bar")
        .attr("x", function (d) {
        return x(d.hour);
    })
        .attr("y", function (d) {
        return y(d.max_energy);
    })
        .attr("height", function (d) {
        return height - y(d.max_energy);
    })
        .attr("width", x.rangeBand());
});
</script>

The code calls in a JSON request to a server side script. Here's the data it returns to the browser when executing the query:

[{"hour":"1","max_energy":"15.969"},{"hour":"2","max_energy":"19.065"},{"hour":"3","max_energy":"21.191"},{"hour":"4","max_energy":"23.151"},{"hour":"5","max_energy":"24.403"},{"hour":"6","max_energy":"25.082"},{"hour":"7","max_energy":"25.494"},{"hour":"8","max_energy":"25.499"},{"hour":"9","max_energy":"4.685"},{"hour":"10","max_energy":"7.309"},{"hour":"11","max_energy":"10.051"},{"hour":"12","max_energy":"13.119"}]

My HTML contains this tag where I want the chart to appear:

<sgv class="day_chart"></svg>

I can see the data passing into the JS above via the "alert" function in the data.forEach(function (d), so the data es back.

The page loads but it loads with a blank area where the chart would go, and no JS errors in the console. Thanks for any advice!

I am using D3 for the first time and I have followed the instructions on their site to get to this point. I cannot seem to get the chart to display although there are no exceptions in the JS console in Chrome.

Here's the JS in the header of my page:

<script>
    var margin = {
    top: 0,
    right: 0,
    bottom: 10,
    left: 0
},
width = 838 - margin.left - margin.right,
    height = 300 - margin.top - margin.bottom;

var x = d3.scale.ordinal()
    .rangeRoundBands([0, width], .1);

var y = d3.scale.linear()
    .range([height, 0]);

var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom");

var yAxis = d3.svg.axis()
    .scale(y)
    .orient("left");

var chart = d3.select(".day_chart")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
    .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

d3.json("http://solarmonitoringaustralia..au/myphp/inverterdata.php?var=TEST1&id=C120031", function (error, data) {

    data.forEach(function (d) {
        d.hour = +d.hour; // coerce to number
        d.max_energy = +d.max_energy;

        alert(d.hour + " -- " + d.max_energy);
    });

    x.domain(data.map(function (d) {
        return d.hour;
    }));
    y.domain([0, d3.max(data, function (d) {
        return d.max_energy;
    })]);

    chart.append("g")
        .attr("class", "x axis")
        .attr("transform", "translate(0," + height + ")")
        .call(xAxis);

    chart.append("g")
        .attr("class", "y axis")
        .call(yAxis);

    chart.selectAll(".bar")
        .data(data)
        .enter().append("rect")
        .attr("class", "bar")
        .attr("x", function (d) {
        return x(d.hour);
    })
        .attr("y", function (d) {
        return y(d.max_energy);
    })
        .attr("height", function (d) {
        return height - y(d.max_energy);
    })
        .attr("width", x.rangeBand());
});
</script>

The code calls in a JSON request to a server side script. Here's the data it returns to the browser when executing the query:

[{"hour":"1","max_energy":"15.969"},{"hour":"2","max_energy":"19.065"},{"hour":"3","max_energy":"21.191"},{"hour":"4","max_energy":"23.151"},{"hour":"5","max_energy":"24.403"},{"hour":"6","max_energy":"25.082"},{"hour":"7","max_energy":"25.494"},{"hour":"8","max_energy":"25.499"},{"hour":"9","max_energy":"4.685"},{"hour":"10","max_energy":"7.309"},{"hour":"11","max_energy":"10.051"},{"hour":"12","max_energy":"13.119"}]

My HTML contains this tag where I want the chart to appear:

<sgv class="day_chart"></svg>

I can see the data passing into the JS above via the "alert" function in the data.forEach(function (d), so the data es back.

The page loads but it loads with a blank area where the chart would go, and no JS errors in the console. Thanks for any advice!

• javascript
• php
• d3.js

• This example relies on an element with class day_chart to be present -- do you have that? – Lars Kotthoff Commented Dec 21, 2013 at 22:48
• Hi Lars, thanks for the reply. I have amended the post above to include my HTML which has the following tag where I want the chart rendered: <svg class="day_chart"></svg> just like in the examples. – TheRealPapa Commented Dec 21, 2013 at 22:58
• Could you post a plete working example that demonstrates the problem please, preferably somewhere like jsfiddle? – Lars Kotthoff Commented Dec 21, 2013 at 23:03
• Hi Lars, I have built here: jsfiddle/cZxey/4. What I am not sure is, in JFiddle, how to link external JS library and also the link to my server sided script (in d3.json function). Thanks – TheRealPapa Commented Dec 21, 2013 at 23:26
• I have reworked JSfiddle here jsfiddle/cZxey/10 – TheRealPapa Commented Dec 22, 2013 at 0:20

1 Answer 1

Well, this one's going to be a face-palm moment.

The only thing wrong was a typo.

<sgv class="day_chart"></svg>

Should of course be

<svg class="day_chart"></svg>

I've got a working version here http://jsfiddle/cZxey/11/

(I also set the library to load D3, and inserted hard-coded data. For working with the real data, just ment that out. Oh, and increase your bottom padding so your tick mark labels don't get cut off.)

--ABR