Javascript 在google图表中获取柱形图的工具提示数据

Javascript 在google图表中获取柱形图的工具提示数据,javascript,charts,google-visualization,Javascript,Charts,Google Visualization,我正在使用下面的代码使用GoogleVisualizationAPI绘制柱状图 <html> <head> <script type="text/javascript" src="https://www.google.com/jsapi"></script> <script type="text/javascript"> google.load("visualization", "1", {package

我正在使用下面的代码使用GoogleVisualizationAPI绘制柱状图

<html>
<head>
    <script type="text/javascript" src="https://www.google.com/jsapi"></script>
    <script type="text/javascript">
        google.load("visualization", "1", {packages: ["corechart"]});
        google.setOnLoadCallback(drawChart);
        function drawChart() {
            var data = google.visualization.arrayToDataTable([
                ['Year', 'Expenses'],
                ['2004', 400],
                ['2005', 460],
                ['2006', 1120],
                ['2007', 540]
            ]);

            var options = {
                hAxis: {title: 'Year', titleTextStyle: {color: 'red'}}
            };

            var chart = new google.visualization.ColumnChart(document.getElementById('chart_div'));
            chart.draw(data, options);
        }
    </script>
</head>
<body>
    <div id="chart_div" style="width: 900px; height: 500px;"></div>
</body>
</html>

load(“可视化”、“1”、{packages:[“corechart”]});
setOnLoadCallback(drawChart);
函数绘图图(){
var data=google.visualization.arrayToDataTable([
[“年度”、“费用”],
['2004', 400],
['2005', 460],
['2006', 1120],
['2007', 540]
]);
变量选项={
hAxis:{title:'Year',titleTextStyle:{color:'red'}
};
var chart=new google.visualization.ColumnChart(document.getElementById('chart_div'));
图表绘制(数据、选项);
}
当我单击其中一个栏时,它会在工具提示中显示x轴和y轴的数据。我想要在工具提示(2006和460)中显示为警报的数据。如何找到它

使用“选择”事件处理程序,并根据所选元素从数据表中获取数据:

google.visaulization.events.addListener(chart, 'select', function () {
    var selection = chart.getSelection();
    if (selection.length) {
        alert(data.getValue(selection[0].row, 0) + ' ' + data.getValue(selection[0].row, selection[0].column));
    }
});