js導出PDF

js實現導出PDF

<button onclick="aaa()">導出PDF</button>
<div class="right-aside">
    <table border="" cellspacing="" cellpadding="" id="ta">
        <h3>111</h3>
        <thead>
            <tr>
                <td>IU號碼</td>
                <td>車牌號碼</td>
            </tr>
        </thead>
        <tbody></tbody>
    </table>
</div>
<!-- 下面這倆是導出PDF用的 -->
<script src="https://cdn.bootcss.com/html2canvas/0.5.0-beta4/html2canvas.js"></script>
<script src="https://cdn.bootcss.com/jspdf/1.3.4/jspdf.debug.js"></script>
<script>
    //導出PDF方法
    function aaa() {
        //先找到要導出表格的父元素:right-aside,其他啥也不用改了，點擊按鈕調用這個方法就可以了
        var target = document.getElementsByClassName("right-aside")[0];
        target.style.background = "#FFFFFF";

        html2canvas(target, {
            onrendered: function (canvas) {
                var contentWidth = canvas.width;
                var contentHeight = canvas.height;

                //一頁pdf顯示html頁面生成的canvas高度;
                var pageHeight = contentWidth / 592.28 * 841.89;
                //未生成pdf的html頁面高度
                var leftHeight = contentHeight;
                //頁面偏移
                var position = 0;
                //a4紙的尺寸[595.28,841.89]，html頁面生成的canvas在pdf中圖片的寬高
                var imgWidth = 595.28;
                var imgHeight = 592.28 / contentWidth * contentHeight;

                var pageData = canvas.toDataURL('image/jpeg', 1.0);

                var pdf = new jsPDF('', 'pt', 'a4');

                //有兩個高度需要區分，一個是html頁面的實際高度，和生成pdf的頁面高度(841.89)
                //當內容未超過pdf一頁顯示的範圍，無需分頁
                if (leftHeight < pageHeight) {
                    pdf.addImage(pageData, 'JPEG', 0, 0, imgWidth, imgHeight);
                } else {
                    while (leftHeight > 0) {
                        pdf.addImage(pageData, 'JPEG', 0, position, imgWidth, imgHeight)
                        leftHeight -= pageHeight;
                        position -= 841.89;
                        //避免添加空白頁
                        if (leftHeight > 0) {
                            pdf.addPage();
                        }
                    }
                }

                pdf.save("content.pdf");
            }
        })
    }
</script>