I want to check the version of the PDF using client side available options (javascript, HTML5 or others) as i have to validate that PDF version must be 1.3 and if the PDF version is 1.3 than only will upload it in the server.
I know that there are various server side option available for identifying the pdf version but i want the client side available option so user don't need to re-upload the entire file again if it's not Version 1.3
Thanks in advance.
You'll have to use the FileReader API.
Begin by creating a FileReader and registering an onload handler.
As a the first few bytes of a PDF should be plain ASCII we can read them as text and should look something like %PDF-1.3 (where 1.3 is the version) so if we get bytes 5 to 7 (Yes I know it says file.slice(5, 8) I didn't write the spec ;)).
Should be fairly straight forward to drop in to form validation. Left as an exercise for the reader
CAVEAT
This is a simple example and will work for x.x versions but would fail to read versions x.xx properly without modification.
const pdfUpload = document.getElementById('pdfUpload');
const pdfVersion = document.getElementById('pdfVersion');
// wait for input to be "changed"
pdfUpload.addEventListener('change', (e) => {
// grab the selected file
let [file] = e.target.files;
if (!file) return;
// use a FileReader
let reader = new FileReader();
reader.onload = (e) => {
// read the content
let versionString = e.target.result;
pdfVersion.innerText = versionString;
};
// PDF file should start something like '%PDF-1.3'
// grab only the bits we need
reader.readAsText(file.slice(5, 8));
})<input type="file" id="pdfUpload" />
<div>PDF Version: <span id="pdfVersion"></span></div>
readAsBinaryString has not been "standardized` and has actually been deprecated as of July 2012. readAsText also allows you to specify the text encoding and assume UTF-8 unless specified.