html - PHP From Input tag session issue -

html - PHP From Input tag session issue -

switch different php pages , come 1 time again registration page want display previous entered value in input area. how handle session input tag value?. there error code?

<form method="post"> <input id="username" name="username" required="required" type="text" value="<?php echo $_session['username'] ?>" /></form>

have stored post-request?

example

<?php session_start(); if(isset($_post['username']) && strlen(trim($_post['username']))>1)) { $_session['username'] = $_post['username']; } ...

php html session