javascript - how i can exchange y1 axis with y2 axis in nvd3.js? -

i'm newbie in javascript using nvd3.js, want visualize data-data using nvd3.js. have tried nvd3.js , part of code :

var chart;  nv.addgraph(function() { chart = nv.models.lineplusbarchart()     .margin({top: 30, right: 60, bottom: 50, left: 70})     .x(function(d,i) { return })     .color(d3.scale.category10().range());  chart.xaxis   .tickformat(function(d) {       var dx = testdata[0].values[d] && testdata[0].values[d].x || 0;       return dx ? d3.time.format('%x')(new date(dx)) : '';       })   .showmaxmin(false)   .axislabel("x-axis label");  chart.y1axis     .tickformat(d3.format(',f'))     .axislabel("y1axis label");  chart.y2axis     .tickformat(function(d) { return '$' + d3.format(',.2f')(d) })     .axislabel("y2axis label");   chart.bars.forcey([0]).paddata(false); //chart.lines.forcey([0]);   d3.select('#chart1 svg')     .datum(testdata)     .transition().duration(500).call(chart);  nv.utils.windowresize(chart.update);  chart.dispatch.on('statechange', function(e) { nv.log('new state:', json.stringify(e)); });  return chart; 

full code in here : http://jsfiddle.net/8zvlj/2/

i want exchange y1 axis in left side right side , y2 axis in right side left side, have tried, still not work, how can that?

thanks