Chart.js 多工具提示标签

I'm trying to get charts.js to display the label name from each dataset in the tooltip.

My code:

var barChartData = {
    labels : ["January","February","March","April","May","June","July"],
    datasets : [

        {
            label: "Bob",
            fillColor : "rgba(88,196,246,0.5)",
            strokeColor : "rgba(88,196,246,0.8)",
            highlightFill: "rgba(88,196,246,0.75)",
            highlightStroke: "rgba(88,196,246,1)",
            data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
        },
        {
            label: "Tina",
            fillColor : "rgba(74,211,97,0.5)",
            strokeColor : "rgba(74,211,97,0.8)",
            highlightFill : "rgba(74,211,97,0.75)",
            highlightStroke : "rgba(74,211,97,1)",
            data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
        }

    ]
}

var ctx = document.getElementById("canvas").getContext("2d");
window.myBar = new Chart(ctx).Line(barChartData, {
    responsive : true,
    animation: true,
    barValueSpacing : 5,
    barDatasetSpacing : 1,
    tooltipFillColor: "rgba(0,0,0,0.8)",                
    multiTooltipTemplate: "<%= label %> - <%= value %>"

});

With my above code the tooltip when hovering above "January" displays:

January
January - xx
January - xx

Any ideas how I can get it to display the following?

January
Bob - xx
Tina - xx

解决方案

Change

window.myBar = new Chart(ctx).Line(barChartData, {
   responsive : true,
   animation: true,
   barValueSpacing : 5,
   barDatasetSpacing : 1,
   tooltipFillColor: "rgba(0,0,0,0.8)",                
   multiTooltipTemplate: "<%= label %> - <%= value %>"
});

to:

window.myBar = new Chart(ctx).Line(barChartData, {
   responsive : true,
   animation: true,
   barValueSpacing : 5,
   barDatasetSpacing : 1,
   tooltipFillColor: "rgba(0,0,0,0.8)",                
   multiTooltipTemplate: "<%= datasetLabel %> - <%= value %>"
});

The change is to the last line

multiTooltipTemplate: "<%= datasetLabel %> - <%= value %>"

datasetLabel gets the value of the label from the dataset objects (in this case 'Bob' and 'Tina'), whereas label gets the caption printed on the x-axis (part of the labels array)