Bar Transitions with Dynamic Scales

<!DOCTYPE html>
<html lang="en"> 
<head>
 
<meta charset="utf-8">
 
 
<title>Title Here</title>
<script type="text/javascript" src="../d3.v3/d3.v3.js"></script>

var yRange = Math.random()*1000;
for(var i =0; i<10; i++){
	dataset.push(Math.floor(Math.random()*yRange));
}
 
var svg = d3.select("body")
.append("svg")
.attr("width",w)
.attr("height",h);
 
var cVal = d3.scale.category10();
var xScale = d3.scale.ordinal()
								.domain(d3.range(dataset.length)).rangeRoundBands([0,w],0.05);
var yScale = d3.scale.linear()
								.domain([0,d3.max(dataset,function(d){
								return d;
								})])
								.range([h-padding,padding]);
 
console.log(dataset);
	
var xAxis = d3.svg.axis()
				.scale(xScale)
				.orient("bottom");
var yAxis = d3.svg.axis()
				.scale(yScale)
				.orient("left");

svg.append("g")
			.attr("class","x axis")
			.attr("transform","translate("+padding+","+(h-padding)+")")
			.call(xAxis);
svg.append("g")
			.attr("class","y axis")
			.attr("transform", "translate("+padding+","+-10+")")
			.call(yAxis);

svg.selectAll("rect")
		.data(dataset)
		.enter()
	.append("rect")
	.attr("y",function(d,i){
		return yScale(d)-padding-5;
	})
	.attr("x",function(d,i){
		return xScale(i)+padding;
	})
	.attr("height",function(d,i){
		return h-yScale(d);
	})
	.attr("width",xScale.rangeBand())
	.attr("fill",function(d){
		return cVal(d);
	});
	
	
	yRange = Math.random()*1000;
	svg.selectAll("rect")
	.on("click",function(){
		for(var k=0;k<dataset.length;k++){
			dataset[k]=Math.floor(Math.random()*yRange);
		}

yScale = d3.scale.linear()
							.domain([0,d3.max(dataset,function(d){
								return d;
								})])
							.range([h-padding,padding]);

svg.selectAll("rect")
		.data(dataset)
		.transition()
		.duration(1000)
		.delay(function(d,i){
			return i*100;
		})
		.attr("y",function(d){
		return yScale(d)-padding-5;
		})
		.attr("fill",function(d){
			return "rgb("+d*2+",0,0)";
		})
		.attr("height",function(d){
		return h-yScale(d);
		});
 
		svg.selectAll("text").data(dataset).text(function(d){
			return d;
		})
		.attr("x",function(d,i){
			return xScale(i)+padding;
		});
 
		console.log(dataset);
		
	});

</script>
</body>
</html>