代码如下：
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta content="maximum-scale=1.0,minimum-scale=1.0,user-scalable=0,width=device-width,initial-scale=1.0"/> <meta content="telephone=no,email=no,date=no,address=no"> <title>canvas绘制环形进度条</title> <style type="text/css"> .chartbox{width: 100px;margin: 100px auto;} .myChart{width:100px;height: 100px;} </style> </head> <body> <div> <canvas data-total="100" data-curr="29.45"></canvas> </div> <script typet="text/javascript" src="https://libs.baidu.com/jquery/1.9.1/jquery.min.js"></script> <script type="text/javascript"> (function($, window, undefined) { $.fn.ringChart = function(options) { var defaults = { }; var settings = $.extend({}, defaults, options); var canvas = $(this).get(0); var total = $(this).attr("data-total"); var curr = $(this).attr("data-curr"); var constrast = parseFloat(curr/total).toFixed(2); //比例 var context = null; if ( !canvas.getContext) { return; } // 定义开始点的大小 var startArc = Math.PI*1.5; // 根据占的比例画圆弧 var endArc = (Math.PI * 2) * constrast; context = canvas.getContext("2d"); // 圆心文字 context.font="28px Arial"; context.fillStyle = '#ff801a'; context.textBaseline = 'middle'; var text=(Number(curr/total)*100).toFixed(0)+"%"; var tw=context.measureText(text).width; context.fillText(text,50-tw/2,50); // 绘制背景圆 context.save(); context.beginPath(); context.strokeStyle = "#e7e7e7"; context.lineWidth = "4"; context.arc(50, 50, 44, 0, Math.PI * 2, false); context.closePath(); context.stroke(); context.restore(); // 若为百分零则不必再绘制比例圆 if ( curr / total == 0) { return; } // 绘制比例圆 context.save(); context.beginPath(); context.strokeStyle = "#ff801a"; context.lineWidth = "4"; context.arc(50, 50, 44, startArc, (curr % total == 0 ? startArc : (endArc+startArc)), false); context.stroke(); context.restore(); } })($, window); $("#myChart").ringChart(); </script> </body> </html>