JavaScript 实现html导出为PDF文件(63)

 <button id="btn">导出为PDF文件</button>
    <div id="pdfDom">
        <table>
            <th></th>
        </table>
        <ul id="box">
        
<span style="background-color: rgb(255, 255, 255); font-family: tahoma, arial, verdana, sans-serif;">U<font color="#ff0000">ni</font></span><font face="courier new" style="background-color: rgb(255, 255, 255);"><font color="#ff0000">H</font>TML</font><font face="tahoma, arial, verdana, sans-serif" style="color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">Me<i>涂</i></font><div style="color: rgb(0, 0, 0); background-color: rgb(255, 255, 255); font-family: tahoma, arial, verdana, sans-serif;"><br></div><div style="color: rgb(0, 0, 0); font-family: tahoma, arial, verdana, sans-serif;"><span style="background-color: rgb(255, 255, 255);">磊</span><b style=""><span style="background-color: rgb(255, 255, 255);">东奔</span><span style="background-color: rgb(255, 255, 0);">西</span></b><span style="background-color: rgb(255, 255, 0);">走m</span><u style="background-color: rgb(255, 255, 255);">o1
</u></div>    //要打印的HTML 放在这  
        
        
        </ul>
    </div>


<script>
    let obox = document.getElementById("box")
    let opdfdom = $("#pdfDom")
    let obtn = document.getElementById("btn")

 
    obtn.onclick = function(){
        downLoadPdf(opdfdom)
    }
 
    function downLoadPdf(content){
        content = content ? content : null;
        // 条件判断是否打印
        if(!content){
            alert("打印失败，请重新操作")
            return false
        }
        // 开始打印
        console.log(content)
        var contentWidth = content.width();
        var contentHeight = content.height();
        var canvas = document.createElement("canvas")
        canvas.width = contentWidth
        canvas.height = contentHeight
        var context = canvas.getContext("2d");
        html2canvas(content,{
            allowTaint:true,
            scale:2  // 提升画面质量，但是会增加文件大小
        }).then(function(canvas){
            var pdfWidth = canvas.width;
            var pdfHeight = canvas.height;
            var pageHeight = pdfWidth / 592.28 * 841.89;
            var leftHeight = pdfHeight;
            var position = 0;
            var imgWidth = 595.28;
            var imgHeight = 595.28 / pdfWidth * pdfHeight;
            var pageData = canvas.toDataURL("img/jpeg",1.0);
            var pdf = new jsPDF('', 'pt', 'a4');
            // 判断打印dom高度是否需要分页，如果需要进行分页处理
            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
                    if(leftHeight > 0){
                        pdf.addPage()
                    }
                }
            }
            pdf.save("案例.pdf")
        })
 
    }
</script>