In HTML5, the action attribute is no longer required. Remove this attribute when empty.

The admin HTML is served with the HTML5 doctype.

"The action and formaction content attributes, if specified, must have a value that is a valid non-empty URL potentially surrounded by spaces." 
http://www.w3.org/html/wg/drafts/html/master/forms.html#attr-fs-action

Props voldemortensen.
Fixes #30126.


git-svn-id: https://develop.svn.wordpress.org/trunk@31200 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/plugin-install.php

@@ -176,7 +176,7 @@ function install_search_form( $type_selector = true ) {
 		$input_attrs = 'class="wp-filter-search" placeholder="' . esc_attr__( 'Search Plugins' ) . '" ';
 	}
 
-	?><form class="search-form search-plugins" method="get" action="">
+	?><form class="search-form search-plugins" method="get">
 		<input type="hidden" name="tab" value="search" />
 		<?php if ( $type_selector ) : ?>
 		<select name="type" id="typeselector">
@@ -222,7 +222,7 @@ function install_plugins_favorites_form() {
 	$user = ! empty( $_GET['user'] ) ? wp_unslash( $_GET['user'] ) : get_user_option( 'wporg_favorites' );
 	?>
 	<p class="install-help"><?php _e( 'If you have marked plugins as favorites on WordPress.org, you can browse them here.' ); ?></p>
-	<form method="get" action="">
+	<form method="get">
 		<input type="hidden" name="tab" value="favorites" />
 		<p>
 			<label for="user"><?php _e( 'Your WordPress.org username:' ); ?></label>
@@ -253,7 +253,7 @@ function display_plugins_table() {
 	}
 
 	?>
-	<form id="plugin-filter" action="" method="post">
+	<form id="plugin-filter" method="post">
 		<?php $wp_list_table->display(); ?>
 	</form>
 	<?php