当用户单击 GeneratePDF 按钮时，我需要将 html 页面导出为 PDF 文件。我已成功将 HTML 页面导出为 PDF 文件，但只有第一次单击时，我才能将数据下载为 PDF，但第二次单击时，我无法将数据下载为 PDF 文件。我不确定我在代码中哪里出错了。
请检查这里的代码：
$(function() {
var doc = new jsPDF();
var specialElementHandlers = {
'#editor': function(element, renderer) {
return true;
}
};
$('#cmd').click(function() {
doc.fromHTML($('#target').html(), 15, 15, {
'width': 170,
'elementHandlers': specialElementHandlers
});
doc.save('sample-file.pdf');
});
});<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script type="text/javascript" src="https://code.jquery.com/ui/1.12.0-beta.1/jquery-ui.min.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jspdf/1.1.135/jspdf.min.js"></script>
<script type="text/javascript" src="http://cdn.uriit.ru/jsPDF/libs/adler32cs.js/adler32cs.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/FileSaver.js/2014-11-29/FileSaver.min.js
"></script>
<script type="text/javascript" src="libs/Blob.js/BlobBuilder.js"></script>
<script type="text/javascript" src="http://cdn.immex1.com/js/jspdf/plugins/jspdf.plugin.addimage.js"></script>
<script type="text/javascript" src="http://cdn.immex1.com/js/jspdf/plugins/jspdf.plugin.standard_fonts_metrics.js"></script>
<script type="text/javascript" src="http://cdn.immex1.com/js/jspdf/plugins/jspdf.plugin.split_text_to_size.js"></script>
<script type="text/javascript" src="http://cdn.immex1.com/js/jspdf/plugins/jspdf.plugin.from_html.js"></script>
<script type="text/javascript" src="js/basic.js"></script>
<body id="target">
<div id="content">
<h3>Hello, this is a H3 tag</h3>
<a class="upload">Upload to Imgur</a>
<h2>this is <b>bold</b> <span style="color:red">red</span></h2>
<p>Feedback form with screenshot This script allows you to create feedback forms which include a screenshot, created on the clients browser, along with the form. The screenshot is based on the DOM and as such may not be 100% accurate to the real representation
as it does not make an actual screenshot, but builds the screenshot based on the information available on the page. How does it work? The script is based on the html2canvas library, which renders the current page as a canvas image, by reading the
DOM and the different styles applied to the elements. This script adds the options for the user to draw elements on top of that image, such as mark points of interest on the image along with the feedback they send. It does not require any rendering
from the server, as the whole image is created on the clients browser. No plugins, no flash, no interaction needed from the server, just pure JavaScript! Browser compatibility Firefox 3.5+ Newer versions of Google Chrome, Safari & Opera IE9
</p>
</div>
<button id="cmd">generate PDF</button>
</body>
</html>