Оператор проверки принадлежности к классу
if
Справочник языка
PHP Manual

# Control Structures

## Содержание

- if
- else
- elseif/else if
- Alternative syntax for control structures
- while
- do-while
- for
- foreach
- break
- continue
- switch
- declare
- return
- require
- include
- require_once
- include_once

## Introduction

Any PHP script is built out of a series of statements. A statement can be an assignment, a function call, a loop, a conditional statement or even a statement that does nothing (an empty statement). Statements usually end with a semicolon. In addition, statements can be grouped into a statement-group by encapsulating a group of statements with curly braces. A statement-group is a statement by itself as well. The various statement types are described in this chapter.

Оператор проверки принадлежности к классу
if
Справочник языка
PHP Manual