html2canvas

[sakurahua]

html2canvas怎么给下载的图片改名字和加后缀啊，跪求大佬赐教
贴上代码： html2canvas($("#download")).then(function(canvas) {
var imgUri = canvas.toDataURL("image/png").replace("image/png", "image/octet-stream"); // 获取生成的图片的url
window.location.href= imgUri; // 下载图片
});

[qq_31570703]

//保存海报
function downloadImg(){
	html2canvas($(".active")[0]).then(function (canvas) {
		$('#snapshot').attr('src',canvas.toDataURL('image/png'));
		download(canvas.toDataURL('image/png'));
		msg.alert('海报已下载!');
	});
}	

//下载图片
function download(da){
	let imgData = da;
	this.downloadFile('share.png', imgData);
}

//下载
function downloadFile(fileName, content){
	let aLink = document.createElement('a');
	let blob = this.base64ToBlob(content); //new Blob([content]);
	let evt = document.createEvent("HTMLEvents");
	evt.initEvent("click", true, true);//initEvent 不加后两个参数在FF下会报错  事件类型，是否冒泡，是否阻止浏览器的默认行为
	aLink.download = fileName;
	aLink.href = URL.createObjectURL(blob);
	aLink.click()
}

//base64转blob
function base64ToBlob(code){
	let parts = code.split(';base64,');
	let contentType = parts[0].split(':')[1];
	let raw = window.atob(parts[1]);
	let rawLength = raw.length;
	let uInt8Array = new Uint8Array(rawLength);
	for (let i = 0; i < rawLength; ++i) {
		uInt8Array[i] = raw.charCodeAt(i);
	}
	return new Blob([uInt8Array], {type: contentType});
}