Javascript-js What is the difference between a "constructor" in uppercase and a "constructor" that starts with a double underscore in a class?

In JS, this function, capitalized in the first letter, is as follows:

function Person(){//};

Can be called a "constructor",
In a class, for example: (PHP, for example)

class Man extends Person{    public function __construct()    {        //    } }

__construct()Also called a "constructor",
What's the difference between these two are called "constructors"?

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In JS, this function, capitalized in the first letter, is as follows:

function Person(){//};

Can be called a "constructor",
In a class, for example: (PHP, for example)

class Man extends Person{    public function __construct()    {        //    } }

__construct()Also called a "constructor",
What's the difference between these two are called "constructors"?

Syntax, say PHP also supports the class name function is the construction method, double underline is php5.3 introduced, previously did not support

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