js下载canvas图片到本地

<canvas width="354" height="142"></canvas>

var canvas = document.querySelector('canvas')
var a = document.createElement('a')
a.href = canvas.toDataURL('image/png') // 将画布内的信息导出为png图片数据
a.download = this.bigBarcodeValue.name // 设定下载名称
a.click() // 点击触发下载