Geolocation is much more accurate for devices with GPS, like smartphones

localStorage.setItem("key1", "value1");

//this will print the value
alert(localStorage.getItem("key1"));

localStorage.removeItem("key1");

localStorage.clear();

The same syntax applies to the session storage, with one difference: Instead of localStorage, sessionStorage is used

- sessionStorage()
- localStorage()

- Session Storage is destroyed once the user closes the browser
- Local Storage stores data with no expiration date

You need to be familiar with basic JavaScript in order to understand and use the API

Value

Max

Status: <progress min="0" max="100" value="35"> 
</progress>

100

101

102

200

201

202

204

206

301

304

307

308

400

401

402

403

404

405

406

407

408

409

500

501

502

503

504

int

class Book {
    public $price;
    
    public function price(int $price) {
        $this->price = $price;
    }
}

$book = new Book;

$book->price('k34');

echo $book->price;

Uncaught TypeError: Argument 1 passed to Book::price() must be of the type int, string given

class Foo {
    public function __toString()
    {
        return "Some text about the OBJECT"; 
    }
}
$foo = new Foo();
echo $foo;

__toString

interface Talkative {
    public function talk();
}
class Cat implements Talkative {
    public function talk() {
        return 'Woof' . PHP_EOL;
    }
}
class Dog implements Talkative {
    public function talk() {
        return 'Meow' . PHP_EOL;
    }
}
class Tortoise implements Talkative {
    public function talk() {
        return 'Yak yak yak yak ...' . PHP_EOL;
    }
}

$cat = new Cat;
$dog = new Dog;
$tortoise = new Tortoise;

echo $cat->talk();
echo $dog->talk();
echo $tortoise->talk();

class Bird{
    public $canFly;
    public $legCount;
    public $className;
    
    public function __construct($canFly, $legCount, $className) {
        $this->canFly = $canFly;
        $this->legCount = $legCount;
        $this->className = $className;
    }
    
    public function canFly() {
        return $this->canFly;
    }
    
    public function getLegCount() {
        return $this->legCount;
    }
    
    public function getBirdInfo() {
        $canFly = $this->canFly() ? 'can fly' : 'can not fly';
        return $this->className. ' ' . $canFly . ' and has ' . $this->getLegCount() . ' legs' . PHP_EOL;
    }
}

class Pigeon extends Bird{
    public function __construct($canFly, $legCount) {
        parent::__construct($canFly, $legCount, get_class());
    }
}

class Penguin extends Bird{
    public function __construct($canFly, $legCount) {
        parent::__construct($canFly, $legCount, get_class());
    }
}

$pigeon = new Pigeon(true, 2);
$penguin = new Penguin(false, 2);

echo $pigeon->getBirdInfo();
echo $penguin->getBirdInfo();

$search_array = array('first' => 1, 'second' => 4);
if (array_key_exists('first', $search_array)) {
    echo "The 'first' element is in the array";
}