bar chart transitions (can you tell i like bar charts?)

<!DOCTYPE html>
<meta charset="utf-8">
<style>

body {
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  position: relative;
  width: 960px;
}

path {
stroke: steelblue;
stroke-width: 2;
fill: none;
}

.axis path,
.axis line {
fill: none;
stroke: grey;
stroke-width: 1;
shape-rendering: crispEdges;
}

.axis text {
  font: 10px sans-serif;
}

/*.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}*/

.bar {
  fill: steelblue;
  /*fill-opacity: .9;*/
}

label {
  position: absolute;
  top: 10px;
  right: 10px;
}

</style>
<div id="option">
<select type='select' onchange='updateData(value);' style='color:steelblue;font-size:1.1em;'>
   <option value='year_one' name='2002' selected='true' >2002</option>
   <option value='year_two' name='2003'>2003</option>
   <option value='year_three' name='2004'>2004</option>
   <option value='year_four' name='2005'>2005</option>
   <option value='year_five' name='2006'>2006</option>
   <option value='year_six' name='2007'>2007</option>
   <option value='year_seven' name='2008'>2008</option>
   <option value='year_eight' name='2009'>2009</option>
   <option value='year_nine' name='2010'>2010</option>
   <option value='year_ten' name='2011'>2011</option>
   <option value='year_eleven' name='2012'>2012</option>
   
</select>
</div>

var margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = 560 - margin.left - margin.right,
    height = 300 - margin.top - margin.bottom;

var x = d3.scale.ordinal()
    .rangeRoundBands([0, width], 0.1);

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

//create line of values
var valueline = d3.svg.line()
  .x(function(d) { return x(d.network); })
  .y(function(d) { return y(d.variable); });

var json

d3.json("data.json", function(error, result){
  json = result;
  var data = [];
        json.forEach(function(d){
            data.push({variable: +d['year_one'], network: d['network']});
         });
  x.domain(data.map(function(d) { return d.network; }));
  y.domain([d3.min(data, function(d) { return d.variable; }), d3.max(data, function(d) { return d.variable; })]);

svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis)
    .append("text")
      .attr("y", 26)
      .attr("dx", "50.71em")
      .style("text-anchor", "end")
      .text("network");
  svg.append("g")
      .attr("class", "y axis")
      .call(yAxis)
    .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", ".71em")
      .style("text-anchor", "end")
      .text("viewers");
  
  svg.selectAll(".bar")
  .data(data)
  .enter().append("rect")
  .attr("class", "bar")
  .attr("x", function(d) { return x(d.network); })
  .attr("width", x.rangeBand())
  .attr("y", function(d) { return y(d.variable); })
  .attr("height", function(d) { return height - y(d.variable); });
});

//update data from combobox onChange
function updateData(value) {
        var data = [];
        json.forEach(function(d){
            data.push({variable: +d[value], network: d['network']});
         });
  x.domain(data.map(function(d) { return d.network; }));
  y.domain([d3.min(data, function(d) { return d.variable; }), d3.max(data, function(d) { return d.variable; })]);

// Select the section we want to apply our changes to
    var trans = d3.select("body").transition();
    
    // Make the changes
    var transition = svg.transition().duration(750),
        delay = function(d, i) { return i * 50; };
    
   svg.selectAll(".bar")
     .data(data)
     .transition().duration(750)
     .attr("x", function(d) { return x(d.network); })
     .attr("y", function(d) { return y(d.variable); })
     .attr("height", function(d) { return height - y(d.variable); });
    
    transition.select(".y.axis") // change the y axis
      .call(yAxis);
    };

</script>
</html>

Modified http://d3js.org/d3.v3.min.js to a secure url

https://d3js.org/d3.v3.min.js