javascript - How to keep form values even after page is redirected back -

this not simple "after post" situation, because, page getting redirected here.

i have little bit large form 20 or more input fields.

so, user fills form , submits, , after server-side validation (if there's error), user redirected same page form. no values. so, has fill whole thing every time because 1 wrong input.

so, how on problem...

i have seen people suggesting use $_session hold these data. safe ? have more 20 inputs , that's kind of large amount of data..

if not using php framework, there several ways of doing this.

1) yes, can use $_session store information if encounter invalid field after submission. remember use session_start() in order start/access session. safe method, unless worrying session hijacking; that's different topic, own prevention methods.

2) can have form submit same page form's html (or page/function requiring html form itself). can check @ beginning if $_post not empty or set. if so, can perform field checking things , insert database. if encounter invalid field can continue (or require) form html. still have access $_post , can therefore fill form fields again. code can have

<input type="text" name="first_name" value="<?php if(isset($_post['first_name'])) echo $_post['first_name'];?>" /> 

i believe proper way handle issue because optimal way going hassle of using $_session in way. don't believe need "store" data case.