关于javascript:JS生成海报

下载html2canvas

$("#btn_finished").click(function () {    // 滚动条不置顶，生成的图片会有完好    document.documentElement.scrollTop = 0;    html2canvas(document.querySelector("#theme_poster")).then(canvas => {        var pageData = canvas.toDataURL('image/jpeg', 1.0);        saveFile(pageData.replace("image/jpeg", "image/octet-stream"), new Date()            .getTime() + ".jpeg");    })})var saveFile = function (data, filename) {    var save_link = document.createElementNS('http://www.w3.org/1999/xhtml', 'a');    save_link.href = data;    save_link.download = filename;    var event = document.createEvent('MouseEvents');    event.initMouseEvent('click', true, false, window, 0, 0, 0, 0, 0, false, false, false,        false, 0, null);    save_link.dispatchEvent(event);};

如果生成过程中图片不显示，有可能是逾越问题，须要波及到CORS