[Solved]-NVD3 output date format in tooltip as %d/%m/%y and x-axis date as %d/%m-d3.js

You can create custom tooltips by using chart.tooltip.contentGenerator. Add a line which outputs the date in your desired format. For example:

chart.tooltip.contentGenerator(function (d) {
          var html = "<h2>Date: "+ d3.time.format('%d/%m/%y')(new Date(d.value))+"</h2> <ul>";
          d.series.forEach(function(elem){
            html += "<li><h3 style='color:"+elem.color+"'>"
                    +elem.key+"</h3><b>"+elem.value+"</b></li>";
          })
          html += "</ul>"
          return html;

Here is a working JSFiddle for reference: http://jsfiddle.net/wgmpfa2p/5/