urned by the button

    // A color scale: one color for each group
    var myColor = d3.scaleOrdinal()
      .domain(allGroup)
      .range(d3.schemeSet2);

    // Add X axis --> it is a date format
    var x = d3.scaleLinear()
      .domain([0,10])
      .range([ 0, width ]);
    svg.append("g")
      .attr("transform", "translate(0," + height + ")")
      .call(d3.axisBottom(x));

    // Add Y axis
    var y = d3.scaleLinear()
      .domain( [0,20])
      .range([ height, 0 ]);
    svg.append("g")
      