变量如何在PHP中运行？

Question

Can anyone explain how variables work in PHP?

When I wrote the script to a game (San Andreas Multiplayer, Pawn language), i used variables like this:

new Health = 100;

but it was incorrect, because it was the same variable for all players. So, the correct way was:

new Health[NUMBER_OF_PLAYERS];
Health[player_ID] = 100;

And now, my question is: How do it works in PHP?

When I create a variable

$x = 100;

and two buttons in JS:

• buttonA - that increase value by 1
• buttonB - display current value of variable $x

What will happen, when one user click buttonA few times? The other users will see (by clicking buttonB) value higer than 100, because there is only one variable $x on the server? Or they will see 100, because each user has "own variable"?

Is there a difference, when it's working by AJAX, or directly inserting PHP code into .html file (using <?php tag)?

Answer 1

PHP is a server side language, as such each new connection to the server would have its own variables.

By default, variables are not persistent unless stored in some form, how they are stored, it is completely your choice.

You can globalise the variables by storing them in one centralised location and updating / retrieving them as and when you need for each user.

Using AJAX wouldn't solve the persistence issue of the variable, however, it would cut out the page reload aspect.

Reading Material

Session

Cookies

Database

Memcache