Google图表返回错误 - 未捕获的ReferenceError：未定义mon

Question

我需要在我的项目上实现谷歌图表，但它返回错误，因为我说..我的视图代码 字符串像几个月以及不工作的日子，数字很好..

我从codeigniter控制器和模型获得了这些数据，希望得到答案。

<script type="text/javascript" src="https://www.google.com/jsapi"></script>
<script type="text/javascript">
    google.load("visualization", "1.1", {packages: ['bar', 'timeline']});
    google.setOnLoadCallback(drawChart);
    function drawChart() {
        var data = google.visualization.arrayToDataTable([
            [{type: 'string', label: 'Days'}, {type: 'number', label: 'Viewers'}],
<?php
foreach ($chart_data as $data) {
    $date = strtotime($data->view_time);
    $day = date('D',
            $date); //mon,tue
    echo '[' . $day . ',' . $data->id . '],';
}
?>
        ]);

        var options = {
            chart: {
                title: 'App viewers',
                subtitle: 'Viewers: <?php echo 'Sun' . '-' . 'Sat'; ?>',
            }
        };

        var chart = new google.charts.Bar(document.getElementById('columnchart_material'));

        chart.draw(data, options);
    }
</script>