Rootdiv

// HTML form
<form action="upload.php" method="post" enctype="multipart/form-data">
  <input type="file" name="image" required>
  <button type="submit">Загрузить</button>
</form>

<?php
// File upload.php
// Если в $_FILES существует "image" и она не NULL
if (isset($_FILES['image'])) {

Rootdiv

// HTML form
<form action="upload.php" method="post" enctype="multipart/form-data">
  <input type="file" name="images[]" multiple>
  <button type="submit">Загрузить</button>
</form>

<?php
// File upload.php
// Если в $_FILES существует "images" и она не NULL
if (isset($_FILES['images'])) {

Rootdiv

<div id="app">
	<div class="container">
		<h1 class="title">{{ title }}</h1>
		<div class="card">
			<div class="card__inner">
				<form>
					<input type="text" placeholder="Create a new todo" v-model="newItem" />
					<button @click="addItem" :disabled="newItem.length === 0">Add Todo</button>
				</form>
				<p v-if="items.length === 0">No todos!</p>

Rootdiv

class bootstrap_4_walker_nav_menu extends Walker_Nav_menu {
    
    function start_lvl( &$output, $depth = 0, $args = array() ){ // ul
        $indent = str_repeat("\t",$depth); // indents the outputted HTML
        $submenu = ($depth > 0) ? ' sub-menu' : '';
        $output .= "\n$indent<ul class=\"dropdown-menu$submenu depth_$depth\">\n";
    }
  
  function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ){ // li a span