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<!-- canvas.wxml --> <canvas type="2d" id="myCanvas"></canvas> // canvas.js Page({ onReady() { const query = wx.createSelectorQuery() query.select('#myCanvas') .fields({ node: true, size: true }) .exec((res) => { const canvas = res[0].node const ctx = canvas.getContext('2d') const dpr = wx.getSystemInfoSync().pixelRatio canvas.width = res[0].width * dpr canvas.height = res[0].height * dpr ctx.scale(dpr, dpr) ctx.fillRect(0, 0, 100, 100) }) } }) VM13:2 MiniProgramError U.createEvent is not a function TypeError: U.createEvent is not a function     at Q (eval at n.call.document (http://127.0.0.1:42506/remote-debug/runtime.js?devtools_ignore=true:1:13107), <anonymous>:2:30303)     at eval (eval at n.call.document (http://127.0.0.1:42506/remote-debug/runtime.js?devtools_ignore=true:1:13107), <anonymous>:2:30601)     at e.exports (eval at n.call.document (http://127.0.0.1:42506/remote-debug/runtime.js?devtools_ignore=true:1:13107), <anonymous>:2:35763)     at eval (eval at n.call.document (http://127.0.0.1:42506/remote-debug/runtime.js?devtools_ignore=true:1:13107), <anonymous>:2:30552)     at y.<computed> (eval at n.call.document (http://127.0.0.1:42506/remote-debug/runtime.js?devtools_ignore=true:1:13107), <anonymous>:2:33829)     at O (eval at n.call.document (http://127.0.0.1:42506/remote-debug/runtime.js?devtools_ignore=true:1:13107), <anonymous>:2:33558)     at Function.eval (eval at n.call.document (http://127.0.0.1:42506/remote-debug/runtime.js?devtools_ignore=true:1:13107), <anonymous>:2:33596)     at <setTimeout callback function>     at eval (eval at n.call.document (http://127.0.0.1:42506/remote-debug/runtime.js?devtools_ignore=true:1:13107), <anonymous>:2:110340)     at eval (eval at n.call.document (http://127.0.0.1:42506/remote-debug/runtime.js?devtools_ignore=true:1:13107), <anonymous>:2:101485)