我有一个奇怪的问题,我很困惑,但我相信在这里有人会知道我做错了什么.我的所有日​​期都显示不正确(即6月显示7月,7月显示8月)

我的代码在这里：

// Load the Visualization API and the piechart package.
google.load('visualization','1.0',{'packages':['corechart']});
// Set a callback to run when the Google Visualization API is loaded.
google.setOnLoadCallback(drawVisualization);
// Callback that creates and populates a data table,// instantiates the pie chart,passes in the data and
// draws it.
function drawVisualization() {
    var chartTable = new google.visualization.DataTable();
    chartTable.addColumn('date','Date');
    chartTable.addColumn('number','Sell');
    chartTable.addColumn('number','GP');
    chartTable.addRows(6);
    chartTable.setValue(0,new Date( 2011,06,22 ));
    chartTable.setValue(0,1,1316.90);
    chartTable.setValue(0,2,456.05);
    chartTable.setValue(1,21 ));
    chartTable.setValue(1,1793.70);
    chartTable.setValue(1,531.10);
    chartTable.setValue(2,20 ));
    chartTable.setValue(2,13559.25);
    chartTable.setValue(2,1337.75);
    chartTable.setValue(3,17 ));
    chartTable.setValue(3,3034.15);
    chartTable.setValue(3,892.30);
    chartTable.setValue(4,16 ));
    chartTable.setValue(4,568.45);
    chartTable.setValue(4,175.05);
    chartTable.setValue(5,15 ));
    chartTable.setValue(5,7203.85);
    chartTable.setValue(5,1343.45);
    var date_formatter = new google.visualization.DateFormat({pattern: 'EEE,MMM-d'});
    date_formatter.format(chartTable,0); // Apply format to first column of table
    var currency_formatter = new google.visualization.NumberFormat({prefix: '$'});
    currency_formatter.format(chartTable,1); // Apply format to second column of chart
    currency_formatter.format(chartTable,2); // Apply format to third column of chart
    // Create and draw the visualization.
    chart = new google.visualization.LineChart(document.getElementById('chart'));
    chart.draw(chartTable,{width: 900,height: 400,title: 'Sales Summary',vAxis: {maxValue: 20000,format: '$##,###',viewWindowMode: 'maximized'},hAxis: {direction: -1}
    });

正确显示所有数据除了日期 – 而不是显示在图表6月它显示7月???这个月的同一天,但月份是错的？