I'm the beginner in this language and want to know about the different type of variable are used in PHP.
Since PHP isn't typed, a variable is a variable. $variable = 'one' is, of course, a string, but $variable = 1 can be string or integer (or floating point). PHP doesn't care. If the variable can't be used in the construct (raising a string to a power, for instance), you'll get an error, but if it can be done it will be done (even if that's not what you meant - so you have to be careful how you define things). See http://www.php.net/manual/en/language.types.type-juggling.php for how PHP changes types as needed.