Question

I know that this php code is bad

<?php
$id=$_SESSION['id'];
?>

but it saves from writing that long code !
For better readability we have to loss some memory,
Q-> but is it really bad [if I have 5 such variables in a page] ?

================================================================

Q-> which one works faster ?
1-> mysqli_prepare("sql");
2-> mysql_real_escape_string("input");
mysqli_query("sql");

================================================================

Q-> is it efficient to close mysqli after it’s job is finished in every page ?

Answer 1

Q-> but is it really bad [if i have such 5 variable in page] ?

you should sanitize your input variables!

Q-> which one works fast ?

mysqli_prepare() ist faster in most cases

Q-> is it efficient to close mysqli after it’s job is finish in every page ?

i think it is a good cosing style and should be done!