h5 html2canvas screenshot

setTimeout(() => {
    
    
    autoA();
}, 1000);
// 生成pdf封装的方法
function autoA() {
    
    
    // console.log($('#evalCode_'+evalCode));
    html2canvas($('#main'), {
    
     //截图对象
        //此处可配置详细参数
        // width:window.screen.availWidth,
        // height:window.screen.availHeight,
        // windowWidth:document.body.scrollWidth,
        // windowHeight:document.body.scrollHeight,
        // x:0,
        // y:window.pageYOffset,
        dpi: 192,
        scale: 2,
        logging: false,
        allowTaint: true,
        useCORS: true,
        onrendered: function (canvas) {
    
    
            // console.log(canvas);
            //渲染完成回调canvas
            canvas.id = "mycanvas";

            // 生成base64图片数据
            // var dataUrl = document.createElement("canvas").toDataURL('image/png');  //指定格式，也可不带参数
            var dataUrl = canvas.toDataURL('image/png');  //指定格式，也可不带参数
            var formData = new FormData(); //模拟表单对象
            formData.append("imgData", convertBase64UrlToBlob(dataUrl), "123.png"); //写入数据
            // console.log(dataUrl);
            // console.log(formData);
            // console.log(canvas);
            // console.log(quesHistoryEvalReportId)
            // var pdfId = quesHistoryEvalReportId.replace(/\|/g, "");

            // if (questionnaireBook != "") {
    
    
            //     pdfId = questionnaireBook;
            // }
            var xhr = new XMLHttpRequest(); //数据传输方法
            xhr.open("POST", webServiceUrl + "app/evaluationreport/exportPdf?pdfId=" + pdfId + "&testSubmitTime=" + testSubmitTime); //配置传输方式及地址
            // xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
            xhr.send(formData);
            xhr.onreadystatechange = function () {
    
     //回调函数
                if (xhr.readyState == 4) {
    
    
                    if (xhr.status == 200) {
    
    
                        $(".zhezhao").hide();
                        // $("#afui,#afui .panel").css("position", "absolute");
                        var back = JSON.parse(xhr.responseText);
                        var a = document.getElementById("downPdf");
                        a.download = $(".b_name").html() + ".pdf";
                        a.href = back.data;
                        // a.click()
                        $("body").on("click", "#publish", function () {
    
    
                            a.click()
                        })

                    }
                }

            };
        }
    })
}