只是測試了下，在 谷歌和360上都可以，但是在火狐和ie下面暫時沒有效果，所以先做個小記錄，等解決ie了，再補充。
<!DOCTYPE html>
<head>
<meta name="layout" content="main">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<script type="text/javascript" src="https://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script>
<script type="text/javascript" src="html2canvas.min.js"></script>
</head>
<body>
<div class="" style="background-color: white;">
測試圖片
</div>
<textArea id="textArea" col="20" rows="10" >85488545878445</textArea>
<input class="button" type="button" value="button" onclick="downloadForJS()">測試</input>
</body>
<script type="text/javascript">
function downloadForJS(){
//使用html2canvas 轉換html爲canvas
html2canvas(document.body).then(function(canvas) {
var imgUri = canvas.toDataURL("image/png").replace("image/png", "image/octet-stream"); // 獲取生成的圖片的url
var saveLink = document.createElement( 'a');
saveLink.href =imgUri;
saveLink.download = 'logo.png';
saveLink.click();
/*console.log(imgUri); */
});
}
</script>
</html>