jsPDF变量未定义

Question

我正在尝试使用jsPDF库将我的HTML页面转换为PDF。我把这个库包含在头上了：

<script src="http://mrrio.github.io/jsPDF/dist/jspdf.debug.js"></script>

然后在页面的末尾：

 <script>
function demoFromHTML() {
    var pdf = new jsPDF('p', 'pt', 'letter');
    // source can be HTML-formatted string, or a reference
    // to an actual DOM element from which the text will be scraped.
    source = $('#content')[0];

    // we support special element handlers. Register them with jQuery-style 
    // ID selector for either ID or node name. ("#iAmID", "div", "span" etc.)
    // There is no support for any other type of selectors 
    // (class, of compound) at this time.
    specialElementHandlers = {
        // element with id of "bypass" - jQuery style selector
        '#bypassme': function (element, renderer) {
            // true = "handled elsewhere, bypass text extraction"
            return true
        }
    };
    margins = {
        top: 80,
        bottom: 60,
        left: 40,
        width: 522
    };
    // all coords and widths are in jsPDF instance's declared units
    // 'inches' in this case
    pdf.fromHTML(
    source, // HTML string or DOM elem ref.
    margins.left, // x coord
    margins.top, { // y coord
        'width': margins.width, // max width of content on PDF
        'elementHandlers': specialElementHandlers
    },

    function (dispose) {
        // dispose: object with X, Y of the last line add to the PDF 
        //          this allow the insertion of new lines after html
        pdf.save('Test.pdf');
    }, margins);
}

最后，我将此代码放在顶部，以便点击打印＆＃39;功能：

<a href="javascript:demoFromHTML()" class="button">Run Code</a><div class="content" id="content"> CONTENT HERE </div>

问题是每次我尝试生成PDF时都会出现以下错误：

TypeError: headers[j] is undefined
rowData[headers[j].name] = tableRow.cells[j].textContent.replace(/\r?\n/g, '');

有什么特别的原因吗？

编辑：里面的内容是一个长达2页的信息表。