Media: Disable upload button in browser's built-in file uploader if no file is selected.

Props karinchristen, krokodok, stefanvelthuys, hubersen, joedolson, mukesh27, rollybueno, ocean90.
Fixes #63561.


git-svn-id: https://develop.svn.wordpress.org/trunk@60449 602fd350-edb4-49c9-b593-d223f7449a82

Author: ocean90

src/wp-admin/css/forms.css

@@ -1592,10 +1592,6 @@ table.form-table td .updated p {
 		line-height: 0.76190476;
 	}
 
-	.wp-upload-form input[type="submit"] {
-		margin-top: 10px;
-	}
-
 	.wp-core-ui select,
 	.wp-admin .form-table select {
 		min-height: 40px;

src/wp-admin/css/themes.css

@@ -2013,6 +2013,10 @@ body.full-overlay-active {
 	.upload-plugin .wp-upload-form {
 		display: block;
 	}
+
+	:is(.upload-theme, .upload-plugin) .wp-upload-form input[type="submit"] {
+		margin-top: 10px;
+	}
 }
 
 @media aural {

src/wp-admin/includes/media.php

@@ -2285,7 +2285,7 @@ function media_upload_form( $errors = null ) {
 			_ex( 'Upload', 'verb' );
 			?>
 		</label>
-		<input type="file" name="async-upload" id="async-upload" />
+		<input type="file" name="async-upload" id="async-upload" required />
 		<?php submit_button( _x( 'Upload', 'verb' ), 'primary', 'html-upload', false ); ?>
 		<a href="#" onclick="try{top.tb_remove();}catch(e){}; return false;"><?php _e( 'Cancel' ); ?></a>
 	</p>

src/wp-admin/media-new.php

@@ -64,7 +64,7 @@
 
 require_once ABSPATH . 'wp-admin/admin-header.php';
 
-$form_class = 'media-upload-form type-form validate';
+$form_class = 'wp-upload-form media-upload-form type-form validate';
 
 if ( get_user_setting( 'uploader' ) || isset( $_GET['browser-uploader'] ) ) {
 	$form_class .= ' html-uploader';