window.onload = function () { var dps = []; // dataPoints var chart = new CanvasJS.Chart('chartContainer', { title: { text: 'Live ECG Data', }, data: [ { type: 'line', dataPoints: dps, }, ], }); var xVal = 0; var yVal = 100; var updateInterval = 1000; // 更新间隔,单位毫秒 var dataLength = 20; // 一次显示的数据点数量 var updateChart = function (count) { count = count || 1; for (var j = 0; j dataLength) { dps.shift(); } chart.render(); }; updateChart(dataLength); // 初始化图表 setInterval(function () { updateChart(); }, updateInterval); // 定时更新图表 };  