I have some suggestions, but it will be definitely difficult to implement. Good luck
First approach:
First use a library like pdf-renderer ( https://pdf-renderer.dev.java.net/ ) to convert the PDF to an image. Store these images on your server or use the caching technique. Converting PDF to image is not difficult.
Type Select JavaScript (http://www.typeselect.org/), . , . , . , . .
, .
:
PDF . Type-3 Type-1, () ( , Unicode, ). PDF- (.. ), , (), .
PDF, , ( PDF ) , HTML. HTML (, <H1> <p>, <b> <i>) ( ) ( , , , ) .
PDF- PDF, HTML-. PDF.
. PDF-, Adobe Font. , , ( Adobe Reader, ).
:
, .
(OCR), , . Google. , .
; Type Select PDF , OCR , , , (, = , lol) .