如果静态值有效但 mySQL 中的动态值无效，如何使用 Javascript 在 Chart.js 中显示 JSON 数据？答案

【问题标题】：How can I show JSON data in Chart.js with Javascript if static values are working but dynamic from mySQL are not?如果静态值有效但 mySQL 中的动态值无效，如何使用 Javascript 在 Chart.js 中显示 JSON 数据？
【发布时间】：2016-10-02 21:59:25
【问题描述】：

我有以下格式的 JSON 数据：

{
    "labels": ["12.11.2016", "13.11.2016", "14.11.2016", ...],
    "temperature": ["12", "35", "27", ...],
    "humidity": ["56", "70", "87", ...]
}

并希望在 Chart.js 中显示它。

我已经找到了 this 的例子，但它不知何故不起作用......

我的 Chart.js 代码如下：

<!doctype html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"><meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<script src="/node_modules/chart.js/dist/Chart.bundle.js"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<style>
    canvas{
        -moz-user-select: none;
        -webkit-user-select: none;
        -ms-user-select: none;
    }
</style>
<title>Temperatur und Feuchtigkeit</title>
</head>
<body>
    <div style="width: 100%;"> 
        <canvas id="canvas"></canvas>
    </div>
    <script>
        var data;
        $.get('GetTestData.php', function(dataGet) {
            data = JSON.parse(dataGet);
            //console.log(data['labels']);
        });
        var randomScalingFactor = function() {
            return Math.round(Math.random() * 100);
        };
        var randomColorFactor = function() {
            return Math.round(Math.random() * 255);
        };
        var randomColor = function(opacity) {
            return 'rgba(' + randomColorFactor() + ',' + randomColorFactor() + ',' + randomColorFactor() + ',' + (opacity || '.9') + ')';
        };

        var config = {
            type: 'line',
            data: {
                //labels: ["11.11.2016", "12.11.2016", "13.11.2016", "14.11.2016", "15.11.2016", "16.11.2016", "17.11.2016"],
                labels: labels
                datasets: [{
                    label: "Temperatur",
                    //data: [randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor()],
                    data: temperature
                    fill: false
                }//,
                //{
                //    label: "Feuchtigkeit",
                //    data: [randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor()],
                //    fill: false
                //}]
            },
            options: {
                responsive: true,
                title:{
                    display:true,
                    text:'Temperatur und Feuchtigkeit'
                },
                tooltips: {
                    mode: 'label'
                },
                hover: {
                    mode: 'dataset'
                },
                scales: {
                    xAxes: [{
                        display: true,
                        scaleLabel: {
                            display: true,
                            labelString: 'Datum'
                        }
                    }],
                    yAxes: [{
                        display: true,
                        scaleLabel: {
                            display: true,
                            labelString: 'Wert'
                        },
                        ticks: {
                            suggestedMin: -20,
                            suggestedMax: 250,
                        }
                    }],
                }
            }
        };

        var labels = [], temperature=[], humidity=[];
        data['labels'].forEach(function(singleResult) {
            labels.push(singleResult);
        });
        data['temperature'].forEach(function(singleResult) {
            temperature.push(singleResult);
        });
        data['humidity'].forEach(function(singleResult) {
            humidity.push(singleResult);
        });

        $.each(config.data.datasets, function(i, dataset) {
            dataset.borderColor = randomColor(1.0);
            dataset.backgroundColor = randomColor(1.0);
            dataset.pointBorderColor = randomColor(1.0);
            dataset.pointBackgroundColor = randomColor(1.0);
            dataset.pointBorderWidth = 1;
        });

        window.onload = function() {
            var ctx = document.getElementById("canvas").getContext("2d");
            window.myLine = new Chart(ctx, config);
        };
    </script>
</body>
</html>

使用静态值，我得到一个非常漂亮的图表，如下所示：但是动态数据加载（如上面的代码）不起作用：/这里有人知道吗？

我得到的错误是：

SyntaxError: missing } after property list[Weitere Informationen]

【问题讨论】：

标签： javascript jquery mysql json chart.js

【解决方案1】：

我现在设法自己解决了这个问题，代码如下：

<!doctype html>
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"><meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <script src="/node_modules/chart.js/dist/Chart.bundle.js"></script>
    <script src="http://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
    <style>
        canvas{
            -moz-user-select: none;
            -webkit-user-select: none;
            -ms-user-select: none;
        }
    </style>
    <title>Temperatur und Feuchtigkeit</title>
    </head>
    <body>
        <div style="width: 100%;"> 
            <canvas id="canvas"></canvas>
        </div>
        <script>
            var data = [], labels = [], temperature=[], humidity=[];
            $.get('GetTestData.php', function(dataGet) {
                data = JSON.parse(dataGet);
                data['labels'].forEach(function(singleResult) {
                    labels.push(singleResult);
                });
                data['temperature'].forEach(function(singleResult) {
                    temperature.push(singleResult);
                });
                data['humidity'].forEach(function(singleResult) {
                    humidity.push(singleResult);
                });
                var ctx = document.getElementById("canvas").getContext("2d");
                window.myLine = new Chart(ctx, config);
            });
            var randomScalingFactor = function() {
                return Math.round(Math.random() * 100);
            };
            var randomColorFactor = function() {
                return Math.round(Math.random() * 255);
            };
            var randomColor = function(opacity) {
                return 'rgba(' + randomColorFactor() + ',' + randomColorFactor() + ',' + randomColorFactor() + ',' + (opacity || '.9') + ')';
            };

            var config = {
                type: 'line',
                data: {
                    labels: labels,
                    datasets: [{
                        label: "Temperatur",
                        data: temperature,
                        fill: false
                    },
                    {
                        label: "Feuchtigkeit",
                        data: humidity,
                        fill: false
                    }]
                },
                options: {
                    responsive: true,
                    title:{
                        display:true,
                        text:'Temperatur und Feuchtigkeit'
                    },
                    tooltips: {
                        mode: 'label'
                    },
                    hover: {
                        mode: 'dataset'
                    },
                    scales: {
                        xAxes: [{
                            display: true,
                            scaleLabel: {
                                display: true,
                                labelString: 'Datum'
                            }
                        }],
                        yAxes: [{
                            display: true,
                            scaleLabel: {
                                display: true,
                                labelString: 'Wert'
                            },
                            ticks: {
                                suggestedMin: -20,
                                suggestedMax: 250,
                            }
                        }],
                    }
                }
            };

            $.each(config.data.datasets, function(i, dataset) {
                dataset.borderColor = randomColor(1.0);
                dataset.backgroundColor = randomColor(1.0);
                dataset.pointBorderColor = randomColor(1.0);
                dataset.pointBackgroundColor = randomColor(1.0);
                dataset.pointBorderWidth = 1;
            });

            window.onload = function() {
                var ctx = document.getElementById("canvas").getContext("2d");
                window.myLine = new Chart(ctx, config);
            };
        </script>
    </body>
    </html>

结果如下：

【讨论】：