Example: Customize a Chart's Tooltip

This example shows how to customize the default tooltip of a Chart.

This example shows how to customize the tooltip for a Chart.

A Chart instance comes with a simple default tooltip. This tooltip is represented by the tooltip attribute. Through the tooltip attribute you can do the following:

  • Style the tooltip background, border and text.
  • Customize and format the tooltip message.
  • Change the show and hide events.
  • Disable the tooltip.

The tooltip attribute contains the following properties:

node
Reference to the actual dom node
showEvent
Event that should trigger the tooltip
hideEvent
Event that should trigger the removal of a tooltip (can be an event or an array of events)
styles
A hash of style properties that will be applied to the tooltip node
show
Indicates whether or not to show the tooltip
markerEventHandler
Displays and hides tooltip based on marker events
planarEventHandler
Displays and hides tooltip based on planar events
markerLabelFunction
Reference to the function used to format a marker event triggered tooltip's text. The method contains the following arguments:
categoryItem
An object containing the following:
axis
The axis to which the category is bound.
displayName
The display name set to the category (defaults to key if not provided).
key
The key of the category.
value
The value of the category.
valueItem
An object containing the following:
axis
The axis to which the item's series is bound.
displayName
The display name of the series. (defaults to key if not provided)
key
The key for the series.
value
The value for the series item.
itemIndex
The index of the item within the series.
series
The CartesianSeries instance of the item.
seriesIndex
The index of the series in the seriesCollection.
The method returns an HTMLElement which is written into the DOM using appendChild. If you override this method and choose to return an html string, you will also need to override the tooltip's setTextFunction method to accept an html string.
planarLabelFunction
Reference to the function used to format a planar event triggered tooltip's text
categoryAxis
CategoryAxis Reference to the categoryAxis of the chart.
valueItems
Array of objects for each series that has a data point in the coordinate plane of the event. Each object contains the following data:
axis
The value axis of the series.
key
The key for the series.
value
The value for the series item.
displayName
The display name of the series. (defaults to key if not provided)
index
The index of the item within its series.
seriesArray
Array of series instances for each value item.
seriesIndex
The index of the series in the seriesCollection.
The method returns an HTMLElement which is written into the DOM using appendChild. If you override this method and choose to return an html string, you will also need to override the tooltip's setTextFunction method to accept an html string.
setTextFunction
Method that writes content returned from planarLabelFunction or markerLabelFunction into the the tooltip node. has the following signature:
label
The HTMLElement that the content is to be added.
val
The content to be rendered into tooltip. This can be a String or HTMLElement. If an HTML string is used, it will be rendered as a string.

In this example, we have changed the styles and set a custom markerLabelFunction to format the text.

var myDataValues = [ 
    {category:"5/1/2010", Miscellaneous:2000, Expenses:3700, Revenue:2200}, 
    {category:"5/2/2010", Miscellaneous:50, Expenses:9100, Revenue:100}, 
    {category:"5/3/2010", Miscellaneous:400, Expenses:1100, Revenue:1500}, 
    {category:"5/4/2010", Miscellaneous:200, Expenses:1900, Revenue:2800}, 
    {category:"5/5/2010", Miscellaneous:5000, Expenses:5000, Revenue:2650}
];

var myTooltip = {
    styles: { 
        backgroundColor: "#333",
        color: "#eee",
        borderColor: "#fff",
        textAlign: "center"
    },
    markerLabelFunction: function(categoryItem, valueItem, itemIndex, series, seriesIndex)
    {
        var msg = document.createElement("div"),
            underlinedTextBlock = document.createElement("span"),
            boldTextBlock = document.createElement("div");
        underlinedTextBlock.style.textDecoration = "underline";
        boldTextBlock.style.marginTop = "5px";
        boldTextBlock.style.fontWeight = "bold";
        underlinedTextBlock.appendChild(document.createTextNode(valueItem.displayName + " for " + 
                                        categoryItem.axis.get("labelFunction").apply(this, [categoryItem.value, categoryItem.axis.get("labelFormat")])));
        boldTextBlock.appendChild(document.createTextNode(valueItem.axis.get("labelFunction").apply(this, [valueItem.value, {prefix:"$", decimalPlaces:2}])));   
        msg.appendChild(underlinedTextBlock);
        msg.appendChild(document.createElement("br"));
        msg.appendChild(boldTextBlock); 
        return msg; 
    }
};

var mychart = new Y.Chart({
                    dataProvider:myDataValues, 
                    type:"bar",
                    render:"#mychart", 
                    tooltip: myTooltip
                });

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