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<\/a>We’re not going to delve into the world of SEO and tags \u2013 you can learn more about this here<\/a> and here<\/a>. Tags are important for both search engines and site visitors and are used extensively here at WPMU as well as WordPress heavyweight users such as Variety and WordPress themselves, particularly in the Showcase.<\/p>\n Tags are WordPress’ wild frontier. It is a free-for-all in regards to creation and assignment and this can lead to SEO issues as well as usability issues. Just compare the editor-managed Showcase<\/a> on WordPress.org with the user-managed Plugins Repository<\/a> to see the difference that a little control can bring.<\/p>\n When managing tags we have three main goals:<\/p>\n To meet these goals, we need to ensure that authors assign an acceptable number of tags from a controlled list and prevent them creating new tags.<\/p>\n To do that, we need to:<\/p>\n The Tags meta box uses a single capability (assign-terms) for the ability to both select tags for a post as well as create new tags, so it’s not just a matter of controlling the capabilities to control the adding of a new tag.<\/p>\n It also does not show the tag cloud by default \u2013 it only appears when the user clicks on Choose from the most used tags<\/em> and when it is displayed it only contains those tags that have already been assigned to at least one post.<\/p>\n Rather than replace the built-in meta box with a custom version, we can insert javascript using the admin_footer-post[-new].php<\/em> actions\u00a0to get the results we want:<\/p>\n This javascript gets inserted into the footer of the post edit pages and executes when the page is loaded. It hides the textbox and the add button and then triggers the click event on the Choose from the most used tags<\/em> link to show the tag cloud.<\/p>\n This will make the tag cloud immediately available but will only show those tags that have already been assigned. We need the tag cloud to include those tags that have yet to be used. To get a full list we need to change the arguments passed to the get_terms<\/em> function:<\/p>\n You’ll notice that as well as overriding the hide_empty<\/em> argument, the number argument is also set to override WordPress’ default limit of 45.<\/p>\n For a quick test, add this code to your functions.php<\/em> file, go back to a post edit screen and refresh. You should not see the add tags textbox and button and you should see a full tag cloud.<\/p>\n Surprisingly, there doesn’t appear to be a plugin in the WordPress Repository to handle our pre-save check for tags. Fortunately, there is the Required Categories plugin<\/a>, so we’ll stand on the shoulders of Josh Hartman<\/a> and modify that code to provide our tag check.<\/p>\n Again, more javascript is added via the admin_footer-post[-new].php<\/em> actions, this time to add a callback function when the Save Draft or Published button is clicked to check the number of tags assigned. If it’s outside of the acceptable range then the save action is cancelled.<\/p>\n Change the min_tags<\/em> and max_tags<\/em> variables to suit your own circumstances.<\/p>\n\n
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Step 1 \u2013 Manipulating the post edit Tags meta box<\/h2>\n
\r\nfunction customise_post_tag_metabox() {\r\n<!-- hide the add function and display tag cloud automatically -->\r\n<script>\r\n(function ($) {\r\n\/\/ hide the add tag elements\r\n$(function () {\r\nvar new_tag = $("#new-tag-post_tag"),\r\nparent = new_tag.length ? new_tag.parents('p') : false,\r\nhowto = parent ? parent.parents("#post_tag").find(".howto") : false ;\r\nif (!parent) return false;\r\nparent.hide();\r\nif (howto) howto.hide();\r\n$("#link-post_tag").hide();\r\n});\r\n\/\/ show the tag cloud by triggering the click event on the link\r\n$(window).load(function () {\r\n$("#link-post_tag").trigger("click");\r\n});\r\n})(jQuery);\r\n<\/script>\r\n<?php\r\n}\r\nadd_action('admin_footer-post.php', 'customise_post_tag_metabox');\r\nadd_action('admin_footer-post-new.php', 'customise_post_tag_metabox');\r\n?>\r\n<\/pre>\n\r\nfunction get_all_tags($args){\r\n\/\/ only show all tags when in the admin interface\r\nif ( is_admin() ) {\r\n$args['hide_empty'] = false;\r\n$args['number'] = '';\r\n}\r\nreturn $args;\r\n}\r\nadd_filter( 'get_terms_args', 'get_all_tags' );\r\n?>\r\n<\/pre>\nStep 2 \u2013 Adding a pre-save tag check to the post edit screen<\/h2>\n
\r\nfunction post_tag_check(){\r\nglobal $post_type;\r\nif($post_type=='post'){\r\necho "<script>\r\njQuery(function($){\r\nvar min_tags = 2, max_tags = 5;\r\n$('#publish, #save-post').click(function(e){\r\nvar assigned_tags = $('.tagchecklist span').length;\r\nif(assigned_tags < min_tags){\r\nalert('You assigned ' + assigned_tags + ' tags. Please assign at least ' + min_tags + ' tags before publishing this post.');\r\ne.stopImmediatePropagation();\r\nreturn false;\r\n}else if(assigned_tags > max_tags){\r\nalert('You assigned ' + assigned_tags + ' tags. Please assign a maximum of ' + max_tags + ' tags before publishing this post.');\r\ne.stopImmediatePropagation();\r\nreturn false;\r\n}else{\r\nreturn true;\r\n}\r\n});\r\nvar publish_click_events = $('#publish').data('events')['click'];\r\nif(publish_click_events){\r\nif(publish_click_events.length>1){\r\npublish_click_events.unshift(publish_click_events.pop());\r\n}\r\n}\r\nvar save_click_events = $('#save-post').data('events')['click'];\r\nif(save_click_events){\r\nif(save_click_events.length>1){\r\nsave_click_events.unshift(save_click_events.pop());\r\n}\r\n}\r\n});\r\n<\/script>";\r\n}\r\n}\r\nadd_action('admin_footer-post.php', 'post_tag_check');\r\nadd_action('admin_footer-post-new.php', 'post_tag_check');\r\n<\/pre>\n