�签
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(" + 0 + "," + margin.top + ")");
//创建矩形条
var rects=svg.selectAll("rect")
	.data(dataset)
	.enter()
	.append("rect")
	.attr({
		x:function(d,i){ return (i+1)*(width/dataset.length)+margin.left-barWidth/2; },
		y:function(d,i){ return height-identityScale(d); },	//矩形起始纵坐标
		width:f