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javascript 动态更新 chartjs 图表的值

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时间：2020-10-27 08:00:13 　来源:igfitidea点击:

Dynamically update values of a chartjs chart

javascriptchartschart.js

提问by adanlif

I created an basic bar chart using chartjs and it works fine. Now I want to update the values on a time based interval. My problem is that after I created the chart, I do not know how to update its values correctly...

我使用chartjs创建了一个基本的条形图，它工作正常。现在我想以基于时间的间隔更新值。我的问题是，在创建图表后，我不知道如何正确更新其值...

My code:

我的代码：

var ctx = $("#myChart").get(0).getContext("2d");

var dts = [
    {
        fillColor: "rgba(220,220,220,0.5)",
        strokeColor: "rgba(220,220,220,1)",
        data: [0, 0, 0, 0, 0]
    }
];

var data = {
    labels: ["Core#1", "Core#2", "Core#3", "Core#4", "Total"],
    datasets: dts
};

var chart = new Chart(ctx);
chart.Bar(data);

//test code
setInterval( function () {                        
    data.datasets[0].data = [random(), random(), random(), random(), random()];
    chart.Bar(data);

},2000);

in the test code, I am updating the values with datasets[0].data- is this the right way to do it? The problem with this is that everytime I call chart.Bar(), the values are reset to 0 then animated to the random value (like I am recreating the chart). This way, all animations are always from 0 to value which looks strange. I would expect that if I update a value from 50 to 10 the bar would go down to 10 from 50 and not setted to 0 then animated to 10.

在测试代​​码中，我正在更新值datasets[0].data- 这是正确的方法吗？问题是每次我调用时chart.Bar()，值都会重置为 0，然后动画为随机值（就像我重新创建图表一样）。这样，所有动画总是从 0 到看起来很奇怪的值。我希望如果我将值从 50 更新到 10，条形图将从 50 下降到 10，而不是设置为 0，然后动画为 10。

I did not found anything in the docs about this... am I doing something wrong or this is impossible with this library?

我没有在文档中找到任何关于此的内容......我做错了什么还是这个库不可能？

采纳答案by doub1eHyman

Update:Looks like chartjs has been updated (see comment below). There are some examples up that look very nice:

更新：看起来 chartjs 已经更新（见下面的评论）。有一些例子看起来很不错：

  1. Here's an example of updating a line chart using new data: http://jsbin.com/yitep/5/edit
  2. Here's how we can update existing data on a line chart: http://jsbin.com/yitep/4/edit
  1. 以下是使用新数据更新折线图的示例：http: //jsbin.com/yitep/5/edit
  2. 以下是我们如何更新折线图上的现有数据：http: //jsbin.com/yitep/4/edit

Original Post

原帖

As of Nov 2013, there seem to be very few options for updating charts.

截至 2013 年 11 月，更新图表的选项似乎很少。

There is a good example here(duplicated below) of adding new points to a line chart. Still kind of jumpy but not too bad. However, I think the effect probably depends on the chart you are using.

这里有一个向折线图添加新点的好例子（复制如下）。仍然有点神经质，但还不错。但是，我认为效果可能取决于您使用的图表。

It does look like this is somewhere in the development pipeline. I don't see any indication of a release date yet though: https://github.com/nnnick/Chart.js/issues/13[Closed as of Jul 26, 2014]

看起来这确实是在开发管道中的某个地方。我还没有看到任何发布日期的迹象：https: //github.com/nnnick/Chart.js/issues/13[截至 2014 年 7 月 26 日关闭]

JS

JS

$(document).ready(function(){
  var count = 10;
  var data = {
      labels : ["1","2","3","4","5", "6", "7", "8", "9", "10"],
        datasets : [
          {
                fillColor : "rgba(220,220,220,0.5)",
                strokeColor : "rgba(220,220,220,1)",
                pointColor : "rgba(220,220,220,1)",
                pointStrokeColor : "#fff",
                data : [65,59,90,81,56,45,30,20,3,37]
            },
            {
                fillColor : "rgba(151,187,205,0.5)",
                strokeColor : "rgba(151,187,205,1)",
                pointColor : "rgba(151,187,205,1)",
                pointStrokeColor : "#fff",
                data : [28,48,40,19,96,87,66,97,92,85]
            }
        ]
  }
  // this is ugly, don't judge me
  var updateData = function(oldData){
    var labels = oldData["labels"];
    var dataSetA = oldData["datasets"][0]["data"];
    var dataSetB = oldData["datasets"][1]["data"];

    labels.shift();
    count++;
    labels.push(count.toString());
    var newDataA = dataSetA[9] + (20 - Math.floor(Math.random() * (41)));
    var newDataB = dataSetB[9] + (20 - Math.floor(Math.random() * (41)));
    dataSetA.push(newDataA);
    dataSetB.push(newDataB);
    dataSetA.shift();
    dataSetB.shift();    };

  var optionsAnimation = {
    //Boolean - If we want to override with a hard coded scale
    scaleOverride : true,
    //** Required if scaleOverride is true **
    //Number - The number of steps in a hard coded scale
    scaleSteps : 10,
    //Number - The value jump in the hard coded scale
    scaleStepWidth : 10,
    //Number - The scale starting value
    scaleStartValue : 0
  }

  // Not sure why the scaleOverride isn't working...
  var optionsNoAnimation = {
    animation : false,
    //Boolean - If we want to override with a hard coded scale
    scaleOverride : true,
    //** Required if scaleOverride is true **
    //Number - The number of steps in a hard coded scale
    scaleSteps : 20,
    //Number - The value jump in the hard coded scale
    scaleStepWidth : 10,
    //Number - The scale starting value
    scaleStartValue : 0
  }

  //Get the context of the canvas element we want to select
  var ctx = document.getElementById("myChart").getContext("2d");
  var optionsNoAnimation = {animation : false}
  var myNewChart = new Chart(ctx);
  myNewChart.Line(data, optionsAnimation);  

  setInterval(function(){
    updateData(data);
    myNewChart.Line(data, optionsNoAnimation)
    ;}, 2000
  );
});


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b.moveTo(0,d*-1*v(a.datasets[g].data[0],j,k));for(var f=1;f<a.datasets[g].data.length;f++)b.rotate(e),b.lineTo(0,d*-1*v(a.datasets[g].data[f],j,k));b.closePath();b.fillStyle=a.datasets[g].fillColor;b.strokeStyle=a.datasets[g].strokeColor;b.lineWidth=c.datasetStrokeWidth;b.fill();b.stroke();if(c.pointDot){b.fillStyle=a.datasets[g].pointColor;b.strokeStyle=a.datasets[g].pointStrokeColor;b.lineWidth=c.pointDotStrokeWidth;for(f=0;f<a.datasets[g].data.length;f++)b.rotate(e),b.beginPath(),b.arc(0,d*-1*
v(a.datasets[g].data[f],j,k),c.pointDotRadius,2*Math.PI,!1),b.fill(),b.stroke()}b.rotate(e)}b.restore()},b)},I=function(a,c,b){for(var e=0,h=Math.min.apply(Math,[u/2,q/2])-5,f=0;f<a.length;f++)e+=a[f].value;x(c,null,function(d){var g=-Math.PI/2,f=1,j=1;c.animation&&(c.animateScale&&(f=d),c.animateRotate&&(j=d));for(d=0;d<a.length;d++){var l=j*a[d].value/e*2*Math.PI;b.beginPath();b.arc(q/2,u/2,f*h,g,g+l);b.lineTo(q/2,u/2);b.closePath();b.fillStyle=a[d].color;b.fill();c.segmentShowStroke&&(b.lineWidth=
c.segmentStrokeWidth,b.strokeStyle=c.segmentStrokeColor,b.stroke());g+=l}},b)},J=function(a,c,b){for(var e=0,h=Math.min.apply(Math,[u/2,q/2])-5,f=h*(c.percentageInnerCutout/100),d=0;d<a.length;d++)e+=a[d].value;x(c,null,function(d){var k=-Math.PI/2,j=1,l=1;c.animation&&(c.animateScale&&(j=d),c.animateRotate&&(l=d));for(d=0;d<a.length;d++){var m=l*a[d].value/e*2*Math.PI;b.beginPath();b.arc(q/2,u/2,j*h,k,k+m,!1);b.arc(q/2,u/2,j*f,k+m,k,!0);b.closePath();b.fillStyle=a[d].color;b.fill();c.segmentShowStroke&&
(b.lineWidth=c.segmentStrokeWidth,b.strokeStyle=c.segmentStrokeColor,b.stroke());k+=m}},b)},K=function(a,c,b){var e,h,f,d,g,k,j,l,m,t,r,n,p,s=0;g=u;b.font=c.scaleFontStyle+" "+c.scaleFontSize+"px "+c.scaleFontFamily;t=1;for(d=0;d<a.labels.length;d++)e=b.measureText(a.labels[d]).width,t=e>t?e:t;q/a.labels.length<t?(s=45,q/a.labels.length<Math.cos(s)*t?(s=90,g-=t):g-=Math.sin(s)*t):g-=c.scaleFontSize;d=c.scaleFontSize;g=g-5-d;e=Number.MIN_VALUE;h=Number.MAX_VALUE;for(f=0;f<a.datasets.length;f++)for(l=
0;l<a.datasets[f].data.length;l++)a.datasets[f].data[l]>e&&(e=a.datasets[f].data[l]),a.datasets[f].data[l]<h&&(h=a.datasets[f].data[l]);f=Math.floor(g/(0.66*d));d=Math.floor(0.5*(g/d));l=c.scaleShowLabels?c.scaleLabel:"";c.scaleOverride?(j={steps:c.scaleSteps,stepValue:c.scaleStepWidth,graphMin:c.scaleStartValue,labels:[]},z(l,j.labels,j.steps,c.scaleStartValue,c.scaleStepWidth)):j=C(g,f,d,e,h,l);k=Math.floor(g/j.steps);d=1;if(c.scaleShowLabels){b.font=c.scaleFontStyle+" "+c.scaleFontSize+"px "+c.scaleFontFamily;
for(e=0;e<j.labels.length;e++)h=b.measureText(j.labels[e]).width,d=h>d?h:d;d+=10}r=q-d-t;m=Math.floor(r/(a.labels.length-1));n=q-t/2-r;p=g+c.scaleFontSize/2;x(c,function(){b.lineWidth=c.scaleLineWidth;b.strokeStyle=c.scaleLineColor;b.beginPath();b.moveTo(q-t/2+5,p);b.lineTo(q-t/2-r-5,p);b.stroke();0<s?(b.save(),b.textAlign="right"):b.textAlign="center";b.fillStyle=c.scaleFontColor;for(var d=0;d<a.labels.length;d++)b.save(),0<s?(b.translate(n+d*m,p+c.scaleFontSize),b.rotate(-(s*(Math.PI/180))),b.fillText(a.labels[d],
0,0),b.restore()):b.fillText(a.labels[d],n+d*m,p+c.scaleFontSize+3),b.beginPath(),b.moveTo(n+d*m,p+3),c.scaleShowGridLines&&0<d?(b.lineWidth=c.scaleGridLineWidth,b.strokeStyle=c.scaleGridLineColor,b.lineTo(n+d*m,5)):b.lineTo(n+d*m,p+3),b.stroke();b.lineWidth=c.scaleLineWidth;b.strokeStyle=c.scaleLineColor;b.beginPath();b.moveTo(n,p+5);b.lineTo(n,5);b.stroke();b.textAlign="right";b.textBaseline="middle";for(d=0;d<j.steps;d++)b.beginPath(),b.moveTo(n-3,p-(d+1)*k),c.scaleShowGridLines?(b.lineWidth=c.scaleGridLineWidth,
b.strokeStyle=c.scaleGridLineColor,b.lineTo(n+r+5,p-(d+1)*k)):b.lineTo(n-0.5,p-(d+1)*k),b.stroke(),c.scaleShowLabels&&b.fillText(j.labels[d],n-8,p-(d+1)*k)},function(d){function e(b,c){return p-d*v(a.datasets[b].data[c],j,k)}for(var f=0;f<a.datasets.length;f++){b.strokeStyle=a.datasets[f].strokeColor;b.lineWidth=c.datasetStrokeWidth;b.beginPath();b.moveTo(n,p-d*v(a.datasets[f].data[0],j,k));for(var g=1;g<a.datasets[f].data.length;g++)c.bezierCurve?b.bezierCurveTo(n+m*(g-0.5),e(f,g-1),n+m*(g-0.5),
e(f,g),n+m*g,e(f,g)):b.lineTo(n+m*g,e(f,g));b.stroke();c.datasetFill?(b.lineTo(n+m*(a.datasets[f].data.length-1),p),b.lineTo(n,p),b.closePath(),b.fillStyle=a.datasets[f].fillColor,b.fill()):b.closePath();if(c.pointDot){b.fillStyle=a.datasets[f].pointColor;b.strokeStyle=a.datasets[f].pointStrokeColor;b.lineWidth=c.pointDotStrokeWidth;for(g=0;g<a.datasets[f].data.length;g++)b.beginPath(),b.arc(n+m*g,p-d*v(a.datasets[f].data[g],j,k),c.pointDotRadius,0,2*Math.PI,!0),b.fill(),b.stroke()}}},b)},L=function(a,
c,b){var e,h,f,d,g,k,j,l,m,t,r,n,p,s,w=0;g=u;b.font=c.scaleFontStyle+" "+c.scaleFontSize+"px "+c.scaleFontFamily;t=1;for(d=0;d<a.labels.length;d++)e=b.measureText(a.labels[d]).width,t=e>t?e:t;q/a.labels.length<t?(w=45,q/a.labels.length<Math.cos(w)*t?(w=90,g-=t):g-=Math.sin(w)*t):g-=c.scaleFontSize;d=c.scaleFontSize;g=g-5-d;e=Number.MIN_VALUE;h=Number.MAX_VALUE;for(f=0;f<a.datasets.length;f++)for(l=0;l<a.datasets[f].data.length;l++)a.datasets[f].data[l]>e&&(e=a.datasets[f].data[l]),a.datasets[f].data[l]<
h&&(h=a.datasets[f].data[l]);f=Math.floor(g/(0.66*d));d=Math.floor(0.5*(g/d));l=c.scaleShowLabels?c.scaleLabel:"";c.scaleOverride?(j={steps:c.scaleSteps,stepValue:c.scaleStepWidth,graphMin:c.scaleStartValue,labels:[]},z(l,j.labels,j.steps,c.scaleStartValue,c.scaleStepWidth)):j=C(g,f,d,e,h,l);k=Math.floor(g/j.steps);d=1;if(c.scaleShowLabels){b.font=c.scaleFontStyle+" "+c.scaleFontSize+"px "+c.scaleFontFamily;for(e=0;e<j.labels.length;e++)h=b.measureText(j.labels[e]).width,d=h>d?h:d;d+=10}r=q-d-t;m=
Math.floor(r/a.labels.length);s=(m-2*c.scaleGridLineWidth-2*c.barValueSpacing-(c.barDatasetSpacing*a.datasets.length-1)-(c.barStrokeWidth/2*a.datasets.length-1))/a.datasets.length;n=q-t/2-r;p=g+c.scaleFontSize/2;x(c,function(){b.lineWidth=c.scaleLineWidth;b.strokeStyle=c.scaleLineColor;b.beginPath();b.moveTo(q-t/2+5,p);b.lineTo(q-t/2-r-5,p);b.stroke();0<w?(b.save(),b.textAlign="right"):b.textAlign="center";b.fillStyle=c.scaleFontColor;for(var d=0;d<a.labels.length;d++)b.save(),0<w?(b.translate(n+
d*m,p+c.scaleFontSize),b.rotate(-(w*(Math.PI/180))),b.fillText(a.labels[d],0,0),b.restore()):b.fillText(a.labels[d],n+d*m+m/2,p+c.scaleFontSize+3),b.beginPath(),b.moveTo(n+(d+1)*m,p+3),b.lineWidth=c.scaleGridLineWidth,b.strokeStyle=c.scaleGridLineColor,b.lineTo(n+(d+1)*m,5),b.stroke();b.lineWidth=c.scaleLineWidth;b.strokeStyle=c.scaleLineColor;b.beginPath();b.moveTo(n,p+5);b.lineTo(n,5);b.stroke();b.textAlign="right";b.textBaseline="middle";for(d=0;d<j.steps;d++)b.beginPath(),b.moveTo(n-3,p-(d+1)*
k),c.scaleShowGridLines?(b.lineWidth=c.scaleGridLineWidth,b.strokeStyle=c.scaleGridLineColor,b.lineTo(n+r+5,p-(d+1)*k)):b.lineTo(n-0.5,p-(d+1)*k),b.stroke(),c.scaleShowLabels&&b.fillText(j.labels[d],n-8,p-(d+1)*k)},function(d){b.lineWidth=c.barStrokeWidth;for(var e=0;e<a.datasets.length;e++){b.fillStyle=a.datasets[e].fillColor;b.strokeStyle=a.datasets[e].strokeColor;for(var f=0;f<a.datasets[e].data.length;f++){var g=n+c.barValueSpacing+m*f+s*e+c.barDatasetSpacing*e+c.barStrokeWidth*e;b.beginPath();
b.moveTo(g,p);b.lineTo(g,p-d*v(a.datasets[e].data[f],j,k)+c.barStrokeWidth/2);b.lineTo(g+s,p-d*v(a.datasets[e].data[f],j,k)+c.barStrokeWidth/2);b.lineTo(g+s,p);c.barShowStroke&&b.stroke();b.closePath();b.fill()}}},b)},D=window.requestAnimationFrame||window.webkitRequestAnimationFrame||window.mozRequestAnimationFrame||window.oRequestAnimationFrame||window.msRequestAnimationFrame||function(a){window.setTimeout(a,1E3/60)},F={}};

HTML

HTML

<html>
    <head>
        <script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
    </head>
    <body>
        <h1>Live Updating Chart.js</h1>

        <canvas id="myChart" width="400" height="150"></canvas>


    </body>
</html>

回答by Stig Husby

The update()triggers an update of the chart. chart.update( )

所述update()触发图表的更新。图表更新（）

.update(config)

Triggers an update of the chart. This can be safely called after updating the data object. This will update all scales, legends, and then re-render the chart. A configobject can be provided with additional configurationfor the update process.

.update(config)

触发图表更新。这可以在更新数据对象后安全地调用。这将更新所有比例、图例，然后重新渲染图表。甲config对象可以设置有额外的配置更新过程。

update()can be safely called after updating values of one or more existing points within the the data object, rendering the changes in one animated render loop.

update()可以在更新数据对象内一个或多个现有点的值后安全调用，在一个动画渲染循环中渲染更改。

// update the first dataset's value of 'March' to be 50
myBarChart.data.datasets[0].bars[2].value = 50;

// animate update of 'March' from 90 to 50.
myBarChart.update();

回答by Armance

Here is how to do it in the last version of ChartJs:

这是在最新版本的 ChartJs 中如何做到的：

setInterval(function(){
    chart.data.datasets[0].data[5] = 80;
    chart.data.labels[5] = "Newly Added";
    chart.update();
}

Look at this clear video

看看这个清晰的视频

or test it in jsfiddle

或在jsfiddle 中测试

回答by AntonE

You also can use destroy() function. Like this

您也可以使用 destroy() 函数。像这样

 if( window.myBar!==undefined)
     window.myBar.destroy();
 var ctx = document.getElementById("canvas").getContext("2d");
 window.myBar = new Chart(ctx).Bar(barChartData, {
     responsive : true,
 });

回答by reznic

You just need to change the chartObject.data.datasetsvalue and call update()like this:

您只需要更改chartObject.data.datasets值并update()像这样调用：

chartObject.data.datasets = newData.datasets;
chartObject.data.labels = newData.labels;
chartObject.update();

回答by Yu Tian

Remove the canvas dom and add in again.

删除画布 dom 并再次添加。

function renderChart(label,data){

    $("#canvas-wrapper").html("").html('<canvas id="storeSends"></canvas>');
    var lineChartData = {
        labels : label,
        datasets : [
            {
                fillColor : "rgba(49, 195, 166, 0.2)",
                strokeColor : "rgba(49, 195, 166, 1)",
                pointColor : "rgba(49, 195, 166, 1)",
                pointStrokeColor : "#fff",
                data : data
            }
        ]

    }
    var canvas = document.getElementById("storeSends");
    var ctx = canvas.getContext("2d");

    myLine = new Chart(ctx).Line(lineChartData, {
        responsive: true,
        maintainAspectRatio: false
    });
}

回答by Ishara Amarasekera

I think the easiest way is to write a function to update your chart including the chart.update()method. Check out thissimple example I wrote in jsfiddle for a Bar Chart.

我认为最简单的方法是编写一个函数来更新您的图表，包括chart.update()方法。查看我在 jsfiddle 中为条形图编写的这个简单示例。

//value for x-axis
var emotions = ["calm", "happy", "angry", "disgust"];

//colours for each bar
var colouarray = ['red', 'green', 'yellow', 'blue'];

//Let's initialData[] be the initial data set
var initialData = [0.1, 0.4, 0.3, 0.6];

//Let's updatedDataSet[] be the array to hold the upadted data set with every update call
var updatedDataSet;

/*Creating the bar chart*/
var ctx = document.getElementById("barChart");
var barChart = new Chart(ctx, {
  type: 'bar',
  data: {
    labels: emotions,
    datasets: [{
      backgroundColor: colouarray,
      label: 'Prediction',
      data: initialData
    }]
  },
  options: {
    scales: {
      yAxes: [{
        ticks: {
          beginAtZero: true,
          min: 0,
          max: 1,
          stepSize: 0.5,
        }
      }]
    }
  }
});

/*Function to update the bar chart*/
function updateBarGraph(chart, label, color, data) {
  chart.data.datasets.pop();
  chart.data.datasets.push({
    label: label,
    backgroundColor: color,
    data: data
  });
  chart.update();
}

/*Updating the bar chart with updated data in every second. */
setInterval(function() {
  updatedDataSet = [Math.random(), Math.random(), Math.random(), Math.random()];
  updateBarGraph(barChart, 'Prediction', colouarray, updatedDataSet);
}, 1000);
<html>

<head>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.3.0/Chart.min.js"></script>

<body>
    <div>
      <h1>Update Bar Chart</h1>
      <canvas id="barChart" width="800" height="450"></canvas>
    </div>
    <script src="barchart.js"></script>
  </body>
  
</head>

</html>

Hope this helps.

希望这可以帮助。

回答by plus-

I don't think it's possible right now.

我认为现在不可能。

However that's a feature which should come soon, as the author hinted here: https://github.com/nnnick/Chart.js/issues/161#issuecomment-20487775

然而，这是一个应该很快就会出现的功能，正如作者在这里暗示的那样：https: //github.com/nnnick/Chart.js/issues/161#issuecomment-20487775

回答by gladiesobmerga

If destroy() and clear() is not working (just like what i had experience) you can use jquery to remove the canvas and append it again.

如果 destroy() 和 clear() 不起作用（就像我的经验一样），您可以使用 jquery 删除画布并再次附加它。

    $('#chartAmazon').remove();
    $('#chartBar').append('<canvas id="chartAmazon"></canvas>');

    var ctxAmazon = $("#chartAmazon").get(0).getContext("2d");
      var AmazonChart = new Chart(ctxAmazon, {
        type: 'doughnut',
        data: dataAmazon,
        options: optionsA
    });

回答by Pedro Alvares

The simplest way is to replace the canvas element and then call new Chart() again:

最简单的方法是替换 canvas 元素，然后再次调用 new Chart() ：

function reloadMyChart() {
    $('myChart').replaceWith('<canvas id="myChart"></canvas>');
    new Chart(document.getElementById("myChart"), {
        data: yourChartData,
        type: yourChartType,
        options: yourChartOptions
    });
}

Of course, you must replace yourChartData, yourChartType and yourChartOptions with the correct values required to initialize Chart.js. See Chart.js Docs.

当然，您必须用初始化 Chart.js 所需的正确值替换 yourChartData、yourChartType 和 yourChartOptions。请参阅Chart.js 文档。

You can call reloadMyChart function on a button click or any other event you need. Probably you'll add parameters to this function and use these to make a REST call to dynamically update your chart, like this:

您可以在单击按钮或任何其他您需要的事件时调用 reloadMyChart 函数。您可能会向该函数添加参数并使用这些参数进行 REST 调用以动态更新您的图表，如下所示：

function reloadMyChart(param1, param2) {
    $('myChart').replaceWith('<canvas id="myChart"></canvas>');
    $.get("restUrl?param1=" + param1 + "&param2=" + param2 + ",
        function(data) {
            // call new Chart() here and use returned data
        }
    );

Hope it helps! =)

希望能帮助到你！=)

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