PHP === and == operators
In PHP syntax the == operator (two equality signs) returns true if the compared values are equal, even if they are in different types (for example, 7 == “7” is true).
The === operator (three equality signs) returns true only if the compared values are absolutely equal, i.e. they have equivalent types as well (e.g. 7 === “7” returns false but 7 === 7 returns true).
Another example, p == 0 is true for p being 0, but also for p being “0” (a string containing the character 0).
p === 0 is true only when p is 0.
Note that Javascript too provides the === operator.