A working example can be found here.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Simple bar Graph</title>
<script src="http://d3js.org/d3.v3.min.js"></script>
</head>
<body>
<div id="theSVG"></div>
<script>
// the data that sets the height
// of the bars
var dataSet=[10,12,13,74,100]
// setting the height and width of the
// svg where it will be drawn
var h=100;
var w=500;
// start d3 and tell it to make a svg
// with the above attributes (height and width)
var svg=d3.select("#theSVG").append("svg")
.attr("width",w)
.attr("height",h);
// create the bars for the bar chart.
svg.selectAll("rect")
// get the data from aboce
.data(dataSet)
// will repeat for each entry in data
.enter()
// and create a rectangle for each entry
.append("rect")
// set the height of the rectangle
.attr("y",function(d){
return h-d;
})
// set width of rectagles
.attr("width",20)
// draw each rectangle 21px to the right.
.attr("x",function(d,i){
return i*21;
})
// now we use the data to se the height
.attr("height",function(d){
return d;
})
;
</script>
</body>
</html>
Jose Christian 