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我正忙于生成实时数据，为此我正在使用 CanvasJS 的服务，因为它们有非常棒的图表。

我有我的 JSON 数据获取代码，我有我的 html 代码，图表将在其中呈现。但它不会显示图表..所以我在我的网络浏览器中打开了 Inspector 以查看问题出在哪里或问题出在哪里，这就是我得到一个错误：

[错误] ReferenceError：找不到变量：$ 全局代码（myHeart_Chart.html，第 7 行）

我现在拥有的代码：

myHeart_Chart.html

<!DOCTYPE HTML>
<html>

<head>
    <script type="text/javascript">

        $(document).ready(function () {

                $.getJSON("data.php", function (result) {

                var dataPoints = [];

                for (var i = 0; i <= result.length - 1; i++) {
                dataPoints.push({ x: Number(result[i].x), y: Number(result[i].y) });
                }

                var chart = new CanvasJS.Chart("chartContainer", {
                data: [
                {
                dataPoints: dataPoints
                }
                ]
                });

                chart.render();
                });
        });


</script>



<script type="text/javascript" src="canvasjs.min.js"></script>
</head>
<body>
    <div id="chartContainer" style="height: 300px; width:100%;">
    </div>
</body>
</html>

PHP 返回 JSON 数据：

数据.php

   <?php
    //header('Content-Type: application/json');
    $con = mysqli_connect("localhost","root","","WebApplication");

    // Check connection
    if (mysqli_connect_errno($con))
    {
        echo "Failed to connect to DataBase: " . mysqli_connect_error();
    } 
    else
    {
    $data_points = array();

    $result = mysqli_query($con, "SELECT * FROM info");

    while($row = mysqli_fetch_array($result))
    {        
        $point = array("x" => $row['id'] , "y" => $row['acceleration']);

        array_push($data_points, $point);        
    }

        $json =  json_encode($data_points, 32); //define('JSON_NUMERIC_CHECK',32);   // Since PHP 5.3.3
        $json = str_replace("\"", "", $json); //replace all the "" with nothing
         echo $json;

    }
    mysqli_close($con);

    ?>

php首先生成了这个：

[{"x":"1","y":"5"},{"x":"2","y":"5"},{"x":"3","y": "4"},{"x":"4","y":"1"}, {"x":"5","y":"8"},{"x":"6", "y":"9"},{"x":"7","y":"5"},{"x":"8","y":"6"}, {"x": "9","y":"4"},{"x":"10","y":"7"},{"x":"14","y":"7"},{ "x":"15","y":"7"}]

然后我添加了这一行：

 $json =  json_encode($data_points, 32); //define('JSON_NUMERIC_CHECK',32);   // Since PHP 5.3.3
            $json = str_replace("\"", "", $json); //replace all the "" with nothing
             echo $json;

这样输出将是数字：

[{x:1,y:5},{x:2,y:5},{x:3,y:4},{x:4,y:1},{x:5,y:8} ,{x:6,y:9},{x:7,y:5},{x:8,y:6}, {x:9,y:4},{x:10,y:7} ,{x:14,y:7},{x:15,y:7}]

此外：基本上第 7 行是它说的部分：

$（文件）

** 我已经忙于这个 canvasjs 大约 3 周了。我想我不知道用什么替换文档。**

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0 回答 0