Php type operator instanceof

The type operator instanceof does not seem to be mentioned in some php books. in the case of php, I just mentioned that I did not elaborate on it. I just excerpted it from the manual for remarks. The instanceof operator is introduced in PHP5. Is_a () was used before, but is_a () is outdated. it is best... "/> <scripttype =" text/javascript "s-type operator instanceof does not seem to be mentioned in some php books. in php, I just mentioned that I did not elaborate on it. I excerpted from the manual, for remarks. The instanceof operator is introduced in PHP 5. Is_a () was used before, but is_a () is outdated. it is best to use instanceof. 1. used to determine whether a variable belongs to an instance of a class; 2. used to determine whether a variable is an instance inherited from a subclass of a parent class; 3. it is used to determine whether a variable is an instance of an object that implements an interface. Before PHP 5.1.0, if the class name to be checked does not exist, instanceof will call _ autoload (). In addition, a fatal error occurs if the class is not loaded. You can avoid this problem by using dynamic class reference or using a string variable containing the class name: example #6 avoid class name searches and fatal errors caused by instanceof in PHP 5.0