PHP Manual . ... for loops are the most complex loops in PHP. ... The syntax of a for loop is: . for (expr1; expr2; expr3) statement . ... Each of the expressions can be empty. expr2 being empty means the loop should be run indefinitely (PHP implicitly considers it as TRUE , like C). This may not be as useless as you might think, since often you'd want to end the loop using a conditional break statement instead of using the for truth expression. Consider the following examples. ...