Most scripts evaluate conditions and change their behavior accordingly. This facility to make decisions makes your PHP pages dynamic, capable of changing their output according to circumstances. In common with most programming languages, PHP enables you to do this with an if statement.
The if Statement
An if statement is a way of controlling the execution of a statement that follows it (that is, a single statement or a block of code inside braces). The if statement evaluates an expression between parentheses. If this expression results in a true value, the statement is executed. Otherwise, the statement is skipped entirely. This enables scripts to make decisions based on any number of factors.
In the following fragment, we show ...