我对 javascript (jquery/json) 很陌生,我已经编写了这段代码来渲染一个CanvasJS
带有 php/json 数据获取脚本的图表。
但是,当我在其中实现代码时,图表不会显示。当我Console.log()
在网络浏览器中使用它来查找 ReferenceError 时,它说:Can't find variable: $ ...Chart.html:11
我尝试了很多事情,并且阅读了许多 [重复] 问题/答案,说我没有加载 Jquery 库和许多其他选项。我试过实现这一行:
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.4/jquery.min.js"> </script>
而且我尝试了很多变量,但我认为我不明白我可以在我拥有的这两个代码中使用更多..
任何指向正确方向的点都会很棒。
图表.html
<!DOCTYPE HTML>
<html>
<script type="text/javascript" src="canvasjs.min.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.4/jquery.min.js"> </script>
<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>
</head>
<body>
<div id="chartContainer" style="height: 300px; width:100%;">
</div>
</body>
</html>
在上面的代码中,它涉及这部分:
$(文档).ready(函数 () {
以及用于获取 JSON 数据的我的 php:data.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);
?>
我知道堆栈溢出社区总是需要更多信息,但是看在上帝的份上,我不再知道了,我真的很想学习这个。
编辑-1:
这是我所知道的,但没有结果。
<!DOCTYPE HTML>
<html>
<head>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.4/jquery.min.js"> </script>
<script type="text/javascript" src="canvasjs.min.js"></script>
<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>
</head>
<body>
<div id="chartContainer" style="height: 300px; width:100%;">
</div>
</body>
</html>
EDIT-2:默认代码,其工作原理:
这是不使用我的 data.php 代码并使用随机数据点作为数据源的默认代码。它来自 Canvasjs,效果很好。
<!DOCTYPE HTML>
<html>
<head>
<script type="text/javascript">
window.onload = function () {
var dps = []; // dataPoints
var chart = new CanvasJS.Chart("chartContainer",{
title :{
text: "Patient #01"
},
data: [{
type: "line",
dataPoints: dps
}]
});
var xVal = 0;
var yVal = 100;
var updateInterval = 20;
var dataLength = 500; // number of dataPoints visible at any point
var updateChart = function (count) {
count = count || 1;
// count is number of times loop runs to generate random dataPoints.
for (var j = 0; j < count; j++) {
yVal = yVal + Math.round(5 + Math.random() *(-5-5));
dps.push({
x: xVal,
y: yVal
});
xVal++;
};
if (dps.length > dataLength)
{
dps.shift();
}
chart.render();
};
// generates first set of dataPoints
updateChart(dataLength);
// update chart after specified time.
setInterval(function(){updateChart()}, updateInterval);
}
</script>
<script type="text/javascript" src="canvasjs.min.js"></script>
</head>
<body>
<div id="chartContainer" style="height: 300px; width:600px;">
</div>
</body>
</html>