<script src="https://html2canvas.hertzen.com/dist/html2canvas.js"></script>
<script>
// 直接下载到本地
function download_img(element, name) {
    html2canvas(element, h2c_option).then(canvas => {
        a = document.createElement('a');
        document.body.appendChild(a);
        a.download = (name || 'download_img') + ".png";
        // a.href = canvas.toDataURL();
        a.href = canvas.toDataURL("image/png").replace("image/png", "image/octet-stream");
        a.click();
    });
}

// 拷贝到剪贴板
function copy_img(element) {
    html2canvas(element, h2c_option).then(canvas =>
        canvas.toBlob(blob => navigator.clipboard.write([new ClipboardItem({'image/png': blob})]))
    );
}

// 参数选项
function h2c_option() {
    return {
        scale: 1,                   // 可以理解为屏幕像素比例(图像大小比例), 例如Mac Retina高清屏, 默认为:2
        scrollX: 0, 
        scrollY: -window.scrollY,   // 网页上下滚动偏移量, 防止滚动后图像不全
        useCORS: true,              // 跨域支持, 例如其他域名的图片
    }
};
</script>