<?php
/*
Plugin Name: Fix Custom Fields in WP 3.4.2
Version: 0.1
Plugin URI: http://core.trac.wordpress.org/ticket/21829
Description: Implements a workaround for adding and updating custom fields in WordPress 3.4.2.
Author: Sergey Biryukov
Author URI: http://profiles.wordpress.org/sergeybiryukov/
*/

function fix_custom_fields_in_wp342() {
	global $wp_version, $hook_suffix;

	if ( '3.4.2' == $wp_version && in_array( $hook_suffix, array( 'post.php', 'post-new.php' ) ) ) : ?>
<script type="text/javascript">
jQuery(document).delegate( '#addmetasub, #updatemeta', 'hover focus', function() {
	jQuery(this).attr('id', 'meta-add-submit');
});
</script>
<?php
	endif;
}
add_action( 'admin_print_footer_scripts', 'fix_custom_fields_in_wp342' );
?>