Tutoriales XML

https://www.tutorialspoint.com/es/xml/index.htm

https://www.desarrolloweb.com/manuales/manual-introduccion-xml.html

https://www.w3schools.com/xml/default.asp

Ajax simple

  <input type="text" id="nombre">
        <input type="text" id="cantidad">
        <input type="button" id="boton" value="Llamada ajax">
        <div id="resultado"></div>
        <script>
            document.getElementById("boton").addEventListener("click", function () {
                var pepe = new XMLHttpRequest();

                pepe.onreadystatechange = function () {
                    if (this.readyState == 4 && this.status == 200) {
                        document.getElementById('resultado').innerHTML = this.responseText;
                    }
                }
                var nombre=document.getElementById('nombre').value;
                var cantidad=document.getElementById('cantidad').value;
                pepe.open("GET", "datos.php?nombre="+nombre+"&cantidad="+cantidad);
                pepe.send();


            })
        </script>

Hola , que tal estamos

Mantenimiento categorías

<!DOCTYPE html>
<!--
To change this license header, choose License Headers in Project Properties.
To change this template file, choose Tools | Templates
and open the template in the editor.
-->
<html>
    <head>
        <title>Mantenimiento categorías</title>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css">

        <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

        <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js"></script>

        <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>

    </head>
    <body>
        <?php
        require_once 'libreria.php';
        $nombre = filter_input(INPUT_GET, 'nombre', FILTER_SANITIZE_STRING);
        $id = filter_input(INPUT_GET, 'idcategoria', FILTER_VALIDATE_INT);
        if (!empty($nombre)) {
            insertarCategoria($nombre);
        }
        if (!empty($id)) {
            borrarCategoria($id);
        }

        $id = filter_input(INPUT_GET, 'id', FILTER_VALIDATE_INT);
        $nombre = filter_input(INPUT_GET, 'categoria', FILTER_SANITIZE_STRING);
        if (!empty($id) && !empty($nombre)) {
            editarCategoria($id, $nombre);
        }
        ?>
        <h1>Mantenimiento categorías</h1>
        <form>Nombre: <input type="text" name="nombre"><input type="submit" class="btn btn-success"></form>
        <hr/>
        <?php
        listadoCategorias();
        ?>
    </body>
</html>

<!DOCTYPE html>
<!--
To change this license header, choose License Headers in Project Properties.
To change this template file, choose Tools | Templates
and open the template in the editor.
-->
<html>
    <head>
       <title>Editar categoría</title>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css">

        <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

        <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js"></script>

        <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>

    </head>
    <body>
        <?php
        require_once 'libreria.php';
        $id = filter_input(INPUT_GET, 'idcategoria', FILTER_VALIDATE_INT);
        if(!empty($id)){
            $categoria=getCategoria($id);
            
        }
        ?>
        <form action="categorias.php">
            <input type="hidden" name="id" value="<?=$categoria['idcategorias']?>">
            Nombre: <input type="text" name="categoria" value="<?=$categoria['nombre']?>">
            <input type="submit" class="btn btn-success">
        </form>
        <a href="categorias.php">Volver a categorías</a>
    </body>
</html>

<?php

function conectar() {
    $server = "localhost";
    $user = "root";
    $password = "";
    $db = "tienda";
    try {
        $conn = new PDO("mysql:host=$server;dbname=$db", $user, $password, [PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES 'utf8'"]);
        $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        return $conn;
    } catch (Exception $ex) {
        echo $ex->getMessage();
    }
}

function insertarCategoria($name) {
    try {
        $conn = conectar();
        $st = $conn->prepare("insert into categorias (nombre) values (:name)");
        $st->execute(['name' => $name]);
    } catch (Exception $ex) {
        echo $ex->getMessage();
    }
}

function borrarCategoria($id) {
    try {
        $conn = conectar();
        $st = $conn->prepare("delete from categorias where idcategorias=:id");
        $st->execute(['id' => $id]);
    } catch (Exception $ex) {
        echo $ex->getMessage();
    }
}

function editarCategoria($id,$nombre){
    try{
        $conn=conectar();
        $st=$conn->prepare("update categorias set nombre=:nombre where idcategorias=:id");
        $st->execute(['nombre'=>$nombre,'id'=>$id]);
    } catch (Exception $ex) {

    }
}
function getCategorias() {
    try {
        $conn = conectar();
        $st = $conn->prepare("select * from categorias");
        $st->execute();
        $categorias = $st->fetchAll();
        return $categorias;
    } catch (Exception $ex) {
        echo $ex->getMessage();
    }
}

function getCategoria($id) {
    try {
        $conn = conectar();
        $st = $conn->prepare("select * from categorias where idcategorias=:id");
        $st->execute(['id' => $id]);
        $categoria = $st->fetch();
        return $categoria;
    } catch (Exception $ex) {
        echo $ex->getMessage();
    }
}

function listadoCategorias() {
    $categorias = getCategorias();
    ?>
    <table class="table">
        <tr><td>Id</td><td>Nombre</td><td>Acciones</td></tr>
        <?php
        foreach ($categorias as $categoria) {
            ?>
            <tr><td><?= $categoria['idcategorias'] ?></td>
                <td><?= $categoria['nombre'] ?></td>
                <td>
                    <a href="?idcategoria=<?= $categoria['idcategorias'] ?>">Borrar</a>
                    <a href="editar_categoria.php?idcategoria=<?= $categoria['idcategorias'] ?>">Editar</a>
                </td>
            </tr>
            <?php
        }
        ?>
    </table>
    <?php
}

Categorías Sakila

 <h1>Categorías</h1>
        <?php
        require_once 'libreria.php';
        $category = filter_input(INPUT_GET, 'category', FILTER_SANITIZE_STRING);
        $category_id = filter_input(INPUT_GET, 'category_id', FILTER_VALIDATE_INT);
        if (!empty($category)) {
            insertarCategoria($category);
        }
        if(!empty($category_id)){
            borraCategoria($category_id);
        }
        ?>
        <form>
            Categoría: <input type="text" name="category">
            <input type="submit" class="btn btn-success">
        </form>
        <hr/>
        <?php
        listadoCategorias();
        ?>

libreria.php

<?php

function conectar() {
    $server = "localhost";
    $user = "root";
    $password = "";
    $db = "sakila";
    try {
        $conn = new PDO("mysql:host=$server;dbname=$db", $user, $password, [PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES 'utf8'"]);
        $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        return $conn;
    } catch (Exception $ex) {
        echo $ex->getMessage();
    }
}

function insertarCategoria($name) {
    try {
        $conn = conectar();
        $st = $conn->prepare("insert into category (name) values (:name)");
        $st->execute(['name' => $name]);
    } catch (Exception $ex) {
        echo $ex->getMessage();
    }
}

function borraCategoria($id) {
    try {
        $conn = conectar();
        $st = $conn->prepare("delete from category where category_id=:id");
        $st->execute(['id' => $id]);
    } catch (Exception $ex) {
        echo $ex->getMessage();
    }
}
function getCategorias() {
    try {
        $conn = conectar();
        $st = $conn->prepare("select * from category");
        $st->execute();
        $categorias = $st->fetchAll();
        return $categorias;
    } catch (Exception $ex) {
        echo $ex->getMessage();
    }
}



function listadoCategorias() {
    echo "hola";
    $categorias = getCategorias();
    ?>
    <table class="table">
        <tr><td>Id</td><td>Nombre</td><td>Acciones</td></tr>
        <?php
        foreach ($categorias as $categoria) {
            ?>
            <tr><td><?= $categoria['category_id'] ?></td>
                <td><?= $categoria['name'] ?></td>
                <td><a href="?category_id=<?= $categoria['category_id'] ?>">Borrar</a></td>
            </tr>
            <?php
        }
        ?>
    </table>
    <?php
}

BD tienda

CREATE TABLE `tienda`.`categorias` (
  `idcategorias` INT NOT NULL AUTO_INCREMENT,
  `nombre` VARCHAR(100) NOT NULL,
  PRIMARY KEY (`idcategorias`));

CREATE TABLE `tienda`.`productos` (
  `idproductos` INT NOT NULL AUTO_INCREMENT,
  `nombre` VARCHAR(45) NULL,
  `precio` DECIMAL(6,4) NULL,
  `descripcion` VARCHAR(500) NULL,
  `idcategorias` INT NULL,
  PRIMARY KEY (`idproductos`),
  INDEX `fk_categorias_idx` (`idcategorias` ASC),
  CONSTRAINT `fk_categorias`
    FOREIGN KEY (`idcategorias`)
    REFERENCES `tienda`.`categorias` (`idcategorias`)
    ON DELETE RESTRICT
    ON UPDATE RESTRICT);

Como ver una página en navegadores antiguos

Función conectar

function conectar() {
    $server = "localhost";
    $user = "root";
    $password = "";
    $db = "sakila";
    try {
        $conn = new PDO("mysql:host=$server;dbname=$db", $user, $password,[PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES 'utf8'"]);
        $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        return $conn;
    } catch (Exception $ex) {
        echo $ex->getMessage();
    }
}

Select con city

  <?php
        $server = "localhost";
        $user = "root";
        $password = "";
        $db = "sakila";
        try {
            $conn = new PDO("mysql:host=$server;dbname=$db", $user, $password);
            $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

            print_r($_GET);
            $address = filter_input(INPUT_GET, "address");
            $district = filter_input(INPUT_GET, "district");
            $city_id = filter_input(INPUT_GET, "city_id");
            $postal_code = filter_input(INPUT_GET, "postal_code");
            $phone = filter_input(INPUT_GET, "phone");
            if(!empty($address) && !empty($district) &&!empty($city_id) && !empty($phone)){
                $sql="insert into address (address,district,city_id,postal_code,phone) values ";
                $sql.="('$address','$district',$city_id,'$postal_code','$phone')";
                $conn->exec($sql);
            }
            $sql = "select city_id,city from city order by city";
            $resul = $conn->query($sql);
            $ciudades = $resul->fetchAll(PDO::FETCH_ASSOC);
        } catch (Exception $ex) {
            echo $ex->getMessage();
        }
        ?>
        <form>
            Dirección: <input type="text" name="address"><br/>
            Distrito: <input type="text" name="district"><br/>
            Ciudad: <select name="city_id">
                <option value="0">Seleccione la ciudad</option>
                <?php
                foreach ($ciudades as $ciudad) {
                    ?>
                    <option value="<?= $ciudad['city_id'] ?>"><?= $ciudad['city'] ?></option>
                    <?php
                }
                ?>

            </select><br/>
            Código postal: <input type="text" name="postal_code"><br/>
            Teléfono: <input type="text" name="phone"><br/>
            <input type="submit">
        </form>

Galería de imágenes

   <h1>Galería de imágenes</h1>
        <?php
        $borrar= filter_input(INPUT_GET, 'borrar');
        if(!empty($borrar)){
            unlink("images/".$borrar);
        }
        if (isset($_FILES['imagen'])) {
            if (explode("/", $_FILES['imagen']['type'])[0] == 'image') {
                move_uploaded_file($_FILES['imagen']['tmp_name'], "images/" . $_FILES['imagen']['name']);
                ?>
                <div class="alert alert-success alert-dismissible">
                    <button type="button" class="close" data-dismiss="alert">&times;</button>
                    <strong>Ok</strong> El archivo se ha subido con éxito.
                </div>
                <?php
            } else {
                ?>
                <div class="alert alert-danger alert-dismissible">
                    <button type="button" class="close" data-dismiss="alert">&times;</button>
                    <strong>Error</strong> El archivo subido no es de tipo imagen.
                </div>
                <?php
            }
        }
        ?>
        <form action='index.php' method="post" enctype="multipart/form-data">
            <input type="file" name="imagen"  >
            <input type="submit" class="btn btn-success" value="Enviar imagen">
        </form>
        <hr/>
        <div style='display:flex;flex-wrap: wrap;'>
            <?php
            $imagenes = scandir("./images");
            for ($i = 2; $i < count($imagenes); $i++) {
                ?>
                <div class="card" style="width:400px" >
                    <img class="card-img-top" src="images/<?= $imagenes[$i] ?>" alt="Card image">
                    <div class="card-body">
                        <h4 class="card-title"><?= $imagenes[$i] ?></h4>
                        <a href="?borrar=<?= $imagenes[$i] ?>" class="btn btn-danger">Borrar imagen</a>
                    </div>
                </div>
                <?php
            }
            ?>
        </div>

El hombre de la factura de 10000 dólares

https://tecnovortex.com/la-verdadera-anecdota-del-ingeniero-y-el-dueno-de-la-fabrica/