生成a标签调用click跳转
var a = document.createElement('a');
a.href = this.getImageUrl(this.pdfFile);
a.id = "img0091";
a.download="a.pdf"
a.style = "display:none";
document.body.appendChild(a);
document.getElementById("img0091").click();
setTimeout(function () {
document.getElementById("img0091").remove();
}, 600);