uni-app H5点击下载图片

downloadImg: function (){
	const that = this;
	// #ifdef H5
	var $code_img = document.getElementById('code_img');
	console.log($code_img.src)
	// #endif
	uni.downloadFile({
	    url: $code_img.src,
	    success: (res) => {
	        if (res.statusCode === 200) {
				console.log(res.tempFilePath);
				that.saveImg(res.tempFilePath)
			}
		}
	});
},
saveImg: function(url){
	var oA = document.createElement("a");
	oA.download = '';// 设置下载的文件名，默认是'下载'
	oA.href = url;
	document.body.appendChild(oA);
	oA.click();
	oA.remove(); // 下载之后把创建的元素删除
},