frontEnd++：使用 html2canvas 实现浏览器截图

html2canvas 可以通过纯JS对浏览器网页进行截屏，但截图的精确度还有待提高

gitHub: https://github.com/niklasvh/html2canvas

引用： <script src="https://cdn.bootcss.com/html2canvas/0.5.0-beta4/html2canvas.js"></script>

使用如下：具体详解请查阅官方文档

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8"/>
    <title>网页DOM元素截图</title>
    <script type='text/javascript' th:src='@{/js/jquery-3.2.0.min.js}'></script>
    <script type='text/javascript' th:src='@{/js/screenshot/html2canvas.js}'></script>
</head>
<script type="text/javascript">
    $(function () {
        $('#btn').click(function () {
            //#proMain:要截图的DOM元素
            //useCORS:true:解决跨域问题
            html2canvas(document.querySelector('#cut'), {useCORS: true}).then(function (canvas) {
                //获取年月日作为文件名
                var timers = new Date();
                var fullYear = timers.getFullYear();
                var month = timers.getMonth() + 1;
                var date = timers.getDate();
                var randoms = Math.random() + '';
                //年月日加上随机数
                var numberFileName = fullYear + '' + month + date + randoms.slice(3, 10);
                var imgData = canvas.toDataURL("image/png");
                //保存图片
                var saveFile = function (data, filename) {
                    /* var save_link = document.createElementNS('http://www.w3.org/1999/xhtml', 'a');
                     save_link.href = data;
                     save_link.download = filename;

                     var event = document.createEvent('MouseEvents');
                     event.initMouseEvent('click', true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
                     save_link.dispatchEvent(event);*/
                    /*--------------------------------------------------------方式二----------------------------------------------------*/
                    let triggerDownload = $("<a>").attr("href", data).attr("download", filename).appendTo("body");
                    triggerDownload[0].click();
                    triggerDownload.remove();
                };
                //最终文件名+文件格式
                var filename = numberFileName + '.png';
                // 下载图片(保存图片)
                saveFile(imgData, filename);
                // 把截的图显示在网页上
                var img = document.createElement('img');//创建一个标签
                img.setAttribute('src', imgData);//给标签定义src链接
                document.getElementById('box').appendChild(img);
            })
        })
        // 代理事件(append之后的标签无法设置事件)
        $('#box').on('click', function (e) {
            var target = e.target || e.srcElement;//获取当前点击的对象
            console.log(target.src)
            $('.bigImg').attr('src', target.src);
            $('.bigImg').css('display', 'block')
        });
    });
</script>
<body>
<button >截图</button>
<fieldset>
    <legend>显示图片</legend>
    <div ></div>
</fieldset>

<div >
    <h1>ABC</h1>
</div>
</body>
</html>