Autofocus on first input of add field form

libraries/tbl_properties.inc.php

@@ -787,6 +787,20 @@ if ($action == 'tbl_create.php') {
 </fieldset>
 <div id="properties_message"></div>
 </form>
+<?php 
+if ($action == 'tbl_addfield.php') {
+?>
+<script type="text/javascript">
+// <![CDATA[
+document.forms
+    .<?php echo ($action == 'tbl_create.php' ? 'create_table_form' : 'append_fields_form'); ?>
+    .querySelector('input[name="field_name[0]"]')
+    .focus();
+// ]]>
+</script>
+<?php
+} // end if ($action == 'tbl_addfield.php')
+?>
 
 <div id="enum_editor">
 <a class="close_enum_editor"><?php echo __('Close'); ?></a>