var url = "{{ url_for('send_file', filename=filename) }}"; console.log(url); var file = url; var file_reader = new FileReader(); typedarray = new Uint8Array(file); // Loaded via document.querySelector("#pdf-upload").addEventListener("change", function(e){ var canvasElement = document.querySelector("canvas") var file = e.target.files[0] if(file.type != "application/pdf"){ console.error(file.name, "is not a pdf file.") return } var fileReader = new FileReader(); fileReader.onload = function() { var typedarray = new Uint8Array(this.result); pdfjsLib.getDocument(typedarray).then(function(pdf) { // you can now use *pdf* here console.log("the pdf has ",pdf.numPages, "page(s).") pdf.getPage(pdf.numPages).then(function(page) { // you can now use *page* here var viewport = page.getViewport(2.0); var canvas = document.querySelector("canvas") canvas.height = viewport.height; canvas.width = viewport.width; page.render({ canvasContext: canvas.getContext('2d'), viewport: viewport }); }); }); }; fileReader.readAsArrayBuffer(file);