How to get the HTML's input element of “file” type to only accept pdf files?

Question

is there any way that html element file

only accept PDF files and when we

Answer 1

It can be useful to prevent the distracted user to make an involuntary bad choice, but in any case, you have to do the check on the server side anyway.
The best way is to be clear in the upload page. After that, if the user stupidly upload a big file with the wrong type, that's their loss of time, no?