我想问一下捕获浏览器窗口屏幕背后的逻辑。我们可以在弹出窗口中打开这个截图图像，用户可以选择保存屏幕截图。
这是我的代码在这段代码中问题是我的浏览器屏幕有图像，它也捕获文本但不捕获图像我无法解决问题所在？这是我的代码
<html lang="en">
<head>
<title>Take Web Page Screenshot with HTML5 and JavaScript </title>
</head>
<body>
<div>
<div style="background-image:url('assets/images/act.png');height: 50px;width: 50px;"></div>
<div><a class="btn btn-success" href="javascript:void(0);" onclick="generate()">Generate
Screenshot »</a>
</div>
<div>fsaffsfasfasfasfasfasff</div>
</div>
<script type="text/javascript">
(function (exports) {
function urlsToAbsolute(nodeList) {
console.log(nodeList);
if (!nodeList.length) {
return [];
}
var attrName = 'href';
if (nodeList[0].__proto__ === HTMLImageElement.prototype || nodeList[0].__proto__===HTMLScriptElement.prototype) {
attrName = 'src';
}
nodeList = [].map.call(nodeList, function (el, i) {
var attr = el.getAttribute(attrName);
if (!attr) {
return;
}
var absURL = /^(https?|data):/i.test(attr);
console.log(absURL);
if (absURL) {
return el;
} else {
return el;
}
});
return nodeList;
}
function screenshotPage() {
urlsToAbsolute(document.images);
urlsToAbsolute(document.querySelectorAll("link[rel='stylesheet']"));
var screenshot = document.documentElement.cloneNode(true);
var b = document.createElement('base');
b.href = document.location.protocol + '//' + location.host;
var head = screenshot.querySelector('head');
head.insertBefore(b, head.firstChild);
screenshot.style.pointerEvents = 'none';
screenshot.style.overflow = 'hidden';
screenshot.style.webkitUserSelect = 'none';
screenshot.style.mozUserSelect = 'none';
screenshot.style.msUserSelect = 'none';
screenshot.style.oUserSelect = 'none';
screenshot.style.userSelect = 'none';
screenshot.dataset.scrollX = window.scrollX;
screenshot.dataset.scrollY = window.scrollY;
var script = document.createElement('script');
script.textContent = '(' + addOnPageLoad_.toString() + ')();';
screenshot.querySelector('body').appendChild(script);
var blob = new Blob([screenshot.outerHTML], {
type: 'text/html'
});
return blob;
}
function addOnPageLoad_() {
window.addEventListener('DOMContentLoaded', function (e) {
var scrollX = document.documentElement.dataset.scrollX || 0;
var scrollY = document.documentElement.dataset.scrollY || 0;
window.scrollTo(scrollX, scrollY);
});
}
function generate() {
window.URL = window.URL || window.webkitURL;
window.open(window.URL.createObjectURL(screenshotPage()));
}
exports.screenshotPage = screenshotPage;
exports.generate = generate;
})(window);
</script>
</body>
</html>