Tahir Yasin

<p>This plugin lists all JavaScripts and Style sheets with a control field that lets you control CSS & JavaScript files to include only on the pages where you actually need them. The text field lets you use WP’s <a href="https://codex.wordpress.org/Conditional_Tags" rel="nofollow ugc">Conditional Tags</a>, or any general PHP code.</p>
<p>NOTE: The script logic you introduce is evaluated directly. Anyone who has permission to manage options will have the right to add any code, including malicious and possibly destructive code. There is an optional filter ‘script_logic_eval_override’ which you can use to bypass the EVAL with your own code if needed. (See <a href="other_notes/" rel="nofollow ugc">Other Notes</a>).</p>
<h3>Writing Logic Code</h3>
<p>The text in the ‘Logic’ field can be full PHP code and should return ‘true’ when you need the script to load. If there is no ‘return’ in the text, an implicit ‘return’ is added to the start and a ‘;’ is added on the end. (This is just to make single statements like is_home() more convenient.)</p>
<h4>The Basics</h4>
<p>Make good use of <a href="https://codex.wordpress.org/Conditional_Tags" rel="nofollow ugc">WP’s own conditional tags</a>. You can vary and combine code using:</p>
<ul>
<li><code>!</code> (NOT) to <strong>reverse</strong> the logic, eg <code>!is_home()</code> is TRUE when this is NOT the home page.</li>
<li><code>||</code> (OR) to <strong>combine</strong> conditions. <code>X OR Y</code> is TRUE when either X is true or Y is true.</li>
<li><code>&&</code> (AND) to make conditions <strong>more specific</strong>. <code>X AND Y</code> is TRUE when both X is true and Y is true.</li>
</ul>
<p>There are lots of great code examples on the WP forums, and on WP sites across the net. But the WP Codex is also full of good examples to adapt, such as <a href="https://codex.wordpress.org/Template_Tags/in_category#Testing_if_a_post_is_in_a_descendant_category" rel="nofollow ugc">Test if post is in a descendent category</a>.</p>
<h4>Examples</h4>
<ul>
<li><code>is_home()</code> — just the main blog page</li>
<li><code>!is_page('about')</code> — everywhere EXCEPT this specific WP ‘page’</li>
<li><code>!is_user_logged_in()</code> — shown when a user is not logged in</li>
<li><code>is_category(array(5,9,10,11))</code> — category page of one of the given category IDs</li>
<li><code>is_single() && in_category('baked-goods')</code> — single post that’s in the category with this slug</li>
<li><code>strpos($_SERVER['HTTP_REFERER'], "google.com")!=false</code> — script to load when clicked through from a google search</li>
<li><code>is_category() && in_array($cat, get_term_children( 5, 'category'))</code> — category page that’s a descendent of category 5</li>
<li><code>global $post; return (in_array(77,get_post_ancestors($post)));</code> — WP page that is a child of page 77</li>
<li><code>global $post; return (is_page('home') || ($post->post_parent=="13"));</code> — home page OR the page that’s a child of page 13</li>
</ul>
<p>Note the extra ‘;’ on the end where there is an explicit ‘return’.</p>
<h3>The ‘script_logic_eval_override’ filter</h3>
<p>Before the Script Logic code is evaluated for each script, the text of the Script Logic code is passed through this filter. If the filter returns a BOOLEAN result, this is used instead to determine if the script should load. Return TRUE to load.</p>


Script Logic

Script Logic lets you control on which pages scripts and style sheets load using WP's conditional tags.

geomagas

<p>This plugin provides an [if] shortcode to conditionally render content. The syntax is the following:</p>
<pre><code>[if condition1 condition2=false condition3]{content}[/if]
</code></pre>
<p>Conditions are passed as attribute names. Multiple conditions evaluate to the result of ORing all of them. In other words, if at least one condition evaluates to the desired boolean result, {content} is rendered, otherwise it is discarded.<br />
Attribute values determine if we want the condition to be true or false. A value of <code>'0'</code>, <code>'false'</code>, <code>''</code> (the empty string), <code>'null'</code> or <code>'no'</code> means we expect the condition to be false. Anything else, including the absense of a value, is interpreted as true.</p>
<p>For example, suppose that we want to include a sentence in a post, but only for anonymous visitors:</p>
<pre><code>[if is_user_logged_in=no]The Sentence.[/if]
</code></pre>
<p>It also provides an [else] shortcode and an [eitherway] one for use inside [if] blocks. [else] will render its content if the condition evaluates to false, and [eitherway] will render its content regardless of the evaluation result.<br />
When used outside an [if] block, these shortcodes behave as if the whole content is surrounded by an [if] shortcode whose condition evaluates to true. In other words, an [else] shortcode would not render any content, while a [eitherway] one would. You can use as many of these shortcodes as you like in a single [if] block, which gives you the ability to do things like:</p>
<pre><code>    - Am I logged in?
    [if is_user_logged_in]- Yes you are.
    [else]- No you are not.
    [/else][eitherway]- I'm sorry, what?
    [/eitherway]- I said YOU A-R-E LOGGED IN!!!
    [else]- YOU ARE NOT LOGGED IN!!! What's the matter with you?[/else][/if]
</code></pre>
<p>A multitude of conditions are supported out-of-the-box. The following evaluate to the result of the corresponding <a href="https://developer.wordpress.org/themes/basics/conditional-tags/" rel="nofollow ugc">WordPress Conditional Tag</a>, using the no-parameter syntax:</p>
<pre><code>    is_single
    is_singular
    is_page
    is_home
    is_front_page
    is_privacy_policy
    is_attachment
    is_category
    is_tag
    is_tax
    is_author
    is_archive
    is_year
    is_month
    is_date
    is_day
    is_time
    is_feed
    is_search
    is_sticky
    is_preview
    has_term
    has_excerpt
    comments_open
    pings_open
    is_404
    is_user_logged_in
    is_super_admin
    is_multi_author
    is_multisite
    is_main_site
    is_child_theme
</code></pre>
<p>For example, the evaluation of the <code>is_page</code> condition is equivalent to calling <code>is_page()</code> with no parameter.</p>
<h3>Extending</h3>
<p>The functionality of the plugin can be extended by other plugins, by means of adding custom conditions through filters. To add a custom condition, a filter hook must be defined in the following manner:</p>
<pre><code>add_filter($if_shortcode_filter_prefix.'my_condition','my_condition_evaluator');

function my_condition_evaluator($value) {
    $evaluate=.... /* add your evaluation code here */
    return $evaluate;
}
</code></pre>
<p>Then, you can use your custom condition like so:</p>
<pre><code>[if my_condition]{content}[/if]
</code></pre>
<p>A big thanks to M Miller for the <a href="http://wordpress.stackexchange.com/a/123073/39275" rel="nofollow ugc"><code>normalize_empty_atts()</code></a> function.</p>


If Shortcode

This plugin provides an [if] shortcode to conditionally render content.

Script Logic vs If Shortcode