What does PHP keyword 'var' do?

Question

This is probably a very trivial question, but I haven't been able to find the answer neither through web search engines, nor on php.net. Please just direct me to where I can read about this, if you haven't got time to explain.

1. What does the 'var' keyword mean in PHP?
2. Are there any differences between PHP4 and PHP5?

Answer 1

It's for declaring class member variables in PHP4, and is no longer needed. It will work in PHP5, but will raise an E_STRICT warning in PHP5 up to version 5.3, as of which it has been deprecated. Example usage:

class foo {
    var $x = 'y';
    function bar() {
    }
}

Answer 2

The var keyword is used to declare variables in a class in PHP 4:

class Foo {
    var $bar;
}

With PHP 5 property and method visibility (public, protected and private) was introduced and thus var is deprecated.

Answer 3

You should consult the PHP reference on their website, php.net.

Here is the section that describes variable declarations: http://us2.php.net/manual/en/language.variables.php

Answer 4

I quote from http://www.php.net/manual/en/language.oop5.visibility.php

Note: The PHP 4 method of declaring a variable with the var keyword is still supported for compatibility reasons (as a synonym for the public keyword). In PHP 5 before 5.1.3, its usage would generate an E_STRICT warning.