# Category: WordPress

## GOAL

Today’s goal is to summarize how to embed inline formula such as $$f(x)=\sqrt{x^2}$$ using plugin “MathJax-LaTeX” in WordPress.

If you haven’t installed “MathJax-LaTeX” yet, add the plug-in and activate it. Check the related article “How To Post Formula on Your WordPress Website”.

## Environment

• WordPress 5.8.2
• MathJax-LaTeX 1.3.11

mathjax

## Method

### Inline formula

Put formula $f(x)=\sqrt{x^2}$ as a test.

Put formula $$f(x)=\sqrt{x^2}$$ as a test.

Put formula $$f(x)=\sqrt{x^2}$$ as a test.

Put formula $$f(x)=\sqrt{x^2}$$ as a test.

### Block formula

Put formula $$f(x)=\sqrt{x^2}$$ as a test.

Put formula $$f(x)=\sqrt{x^2}$$ as a test.

Put formula $f(x)=\sqrt{x^2}$ as a test.

Put formula $f(x)=\sqrt{x^2}$ as a test.

## How To Add Customize Menu for Original WordPress Theme

This is one of the articles about project “Create Original Theme in WordPress”.

## GOAL

Today’s goal is to add original menu to the “Theme Customizer” as below.

The Theme Customizer can be opened from “Appearance” > “Customize” in WordPress admin page.

If the “Excerpt” is selected the excerpts of the post are displayed as page list and if the “Post” is selected the posts themselves are displayed as page list.

WordPress 5.5.1
XAMPP 7.4.10

## Method

Reference: Theme Customization API in wordpress.org

### 1. Define customizer-register function

Add function to register new customizer to the hook “customize_register” in functions.php of your theme.

(more…)

## How to see revision and restore previous article in WordPress

I mistakenly overwrote my article in WordPress. How can I recover them?

## GOAL

To see revisions of the article and recover previous version in WordPress.

WordPress 5.6
Windows 10

## Methods

Open the post and click “Revisions” in right sidebar.

Select the revision you’d like to recover and click “Restore This Revision” button.

## What to do if “Restore This Revision” button is disable

“Restore This Revision” button couldn’t be pressed for some reasons.

You can copy the elements of previous version and paste it into the editor.

## How To Embed HTML Code In WordPress Editor

This is just a tips to embed HTML as a code, not as text.

## GOAL

To embed HTML code in WordPress as below.

### Example 1

<abbr> displays an abbreviation or acronym on mouse over. The tag is <abbr title=”HyperText Markup Language”>HTML</abbr>

This is an example of embedded HTML in WordPress.

(more…)

## Create Original Theme in WordPress 3

At the last time, in “Create Original Theme in WordPress 2“, I designed pages of my original theme “techblog”. Today, I start implementing them.

## GOAL

To study the name of PHP file for each page and create PHP files.

WordPress 5.5.1
XAMPP 7.4.10

## The corresponding PHP files to items

I created these files.

The all files are in https://github.com/s-nako/wordpressTheme/tree/main/techblog.

This is one of the simplest WordPress themes. I’ll customize it in the future.

## Create search.php for original theme

This is one of the articles about project “Create Original Theme in WordPress”.

## GOAL

To create search.php and searchform.php

WordPress 5.5.1
XAMPP 7.4.10

## search.php

It is easy to create search.php by copying and changing from archive.php.

<?php
/**
* The template to display search results
*@package WordPress
*@subpackage Techblog
*@since Techblog 1.0
*/
<div class="container">
<main id="main" class="site-main">
<div class= "main-content">
<?php if ( have_posts() ) :?>
<h1><?php echo esc_html__( 'Search Results for: ', 'techblog' ).'<span>'.esc_html(get_search_query()).'</span>'; ?></h1>
<?php
while ( have_posts() ) :
the_post();
get_template_part( 'content/content', 'search');
endwhile;
the_posts_pagination(
array('prev_text' => '<u>Back<<</u>  ',
'next_text' => '  <u>>>Next</u>', )
);
endif; ?>
</div>
</main>
<?php get_sidebar(); ?>
</div>
<?php
get_footer(); ?>

## Functions

### get_search_query()

This function is used to get the posted search query from the search form. The definition is in wp-includes/general-template.php.

 function get_search_query( $escaped = true ) {$query = apply_filters( 'get_search_query', get_query_var( 's' ) );
if ( $escaped ) {$query = esc_attr( $query ); } return$query;
}

get_query_var( ‘s’ ) is the function to get the value of a query variable from the key ‘s’. So the input form should be named ‘s’.

### get_template_part( $slug,$name = null, $args = array() ) This function is used to get template from {}-{}.php. In my case, get the template from content/content-search.php by using get_template_part( ‘content/content’, ‘search’). But I don’t need content-search.php because the template content/content-search.php is the same as content.php. ## Result ## searchform.php searchform is used as one of the widgets. <?php /** * The search form template *@package WordPress *@subpackage Techblog *@since Techblog 1.0 */ ?> <form role="search" method="get" class="search-form" action="<?php echo esc_url( home_url( '/' ) ); ?>"> <div class="search-group"> <label class="screen-label" for="s"><?php esc_html_e( 'Search:', 'techblog' ); ?></label><br/> <span> <input type="text" class="search-query" placeholder="<?php esc_attr_e('word', 'techblog;' ); ?>" value="<?php echo get_search_query(); ?>" name="s" title="<?php esc_attr_e( 'Search for:', 'techblog' ); ?>"/> <button type="submit" class="search-submit" name="submit" value="<?php esc_attr_e( 'Search', 'techblog' ); ?>"><span class="material-icons">search</span></button> </span> </div> </form>  ## Result ## Change the style ## Create comments.php for original theme This is one of the articles about project “Create Original Theme in WordPress”. ## GOAL To create comments.php ## Environment WordPress 5.5.1 XAMPP 7.4.10 ## Method WordPress has useful function to display comment form and functions to post comments. ## comments.php <?php /** * The comment form for techblog. * @package WordPress * @subpackage Techblog * @since Techblog 1.0 */ if ( post_password_required() ) { return; }?> <div class="comment-area"> <div id="comments" class="comment-main"> <?php if ( have_comments() ) : ?> <h3 class="comments-title"> <?php echo "Comments for ".get_the_title(); ?> </h3> <ol class="comment-list"> <?php wp_list_comments( array( 'style' => 'ol', 'short_ping' => true, ) ); ?> </ol> <?php endif;?> <?php if (!comments_open() && get_comments_number() != '0' && post_type_supports( get_post_type(), 'comments' ) ) :?> <p class="no-comments"><?php esc_html_e( 'Comments are closed.', 'techblog' ); ?></p> <?php endif; comment_form(); ?> </div> </div> ## Functions ### post_password_required() post_password_required() is used to protect contents (posts) with password. This function detect whether post requires password and correct password has been provided. ### have_comments() This returns true if comments are available for current WordPress query. ### wp_list_comments($args = array(), $comments = null) This function is used to displays a list of comments for current post or page. The argument array$args defines formatting options.

Reference: Parameters of wp_list_comments() in wordpress.org

This returns true if the current post is open for comments.

This function return string that represent the number of comments for the current post or page.

### post_type_supports( $post_type,$feature )

This function checks a post type’s support for a given feature. The first argument $post_type is the post type being checked and the second one$feature is the feature being checked.

In my case, get the post type of the current post with get_post_type(), and check if it is ‘comments’.

### comment_form( $args = array(),$post_id = null )

comment_form() is used to output a complete commenting form for use within a template.

This function is used to displays a list of comments for current post or page. The argument array $args defines default arguments and form fields to override. You can use it to change class and id names. Reference: Parameters of comment_form() in wordpress.org ## Result ## Change the style ## Create sidebar.php for original theme This is one of the articles about project “Create Original Theme in WordPress”. ## GOAL To create sidebar.php ## Environment WordPress 5.5.1 XAMPP 7.4.10 ## sidebar.php <?php /** * The template used for the sidebar *@package WordPress *@subpackage Techblog *@since Techblog 1.0 */ ?> <?php if ( is_active_sidebar('sidebar') ) : ?> <aside id="sidebar"> <?php dynamic_sidebar('sidebar'); ?> </aside> <?php endif; ?> ## functions.php ### ‘widgets_init’ ‘widgets_init’ is the hook to initialize widgets such as sidebar. You should hook the register function register_sidebar() with add_action(). Please check the article “What is Hook in WordPress?” for detail about hook in WordPress. In my case, techblog_widgets_init() is the function to register sidebar. /*sidebar*/ function techblog_widgets_init() { register_sidebar( array( 'name' => esc_attr__( 'SideBar', 'techblog' ), 'id' => 'sidebar', 'before_widget' => '<div id="%1$s" class="widget %2$s">', 'after_widget' => '</div>', 'before_title' => '<h3 class="widget-title">', 'after_title' => '</h3>', ) ); } add_action( 'widgets_init', 'techblog_widgets_init' ); ## Add widget Add widgets into the created sidebar into the created sidebar with name “SideBar”. ## Result ## Change the style ## Create footer.php for original theme This is one of the articles about project “Create Original Theme in WordPress”. ## GOAL To create footer.php ## Environment WordPress 5.5.1 XAMPP 7.4.10 ## footer.php <?php /** * The footer for techblog. *@package WordPress *@subpackage Techblog *@since Techblog 1.0 */ ?> <footer class="site-footer" role="contentinfo"> <div class="footer-main"> <div class="footer-info"> <p class="footer-credits"> <span class="footer-copyright"> &copy;<?php echo esc_html( date_i18n('Y') );?> <a href="<?php echo esc_url(home_url());?>" rel="home"><?php bloginfo('name');?></a> </span> <span class="theme-credits"> <?php echo '|Theme by <a href="s-nako.work"> Nako </a>' ?> </span> </p> </div> </div> <div class="scroll-to-top" onclick="location.href='#'"> <span class="material-icons">navigation</span> </div> </footer> <?php wp_footer(); ?> </body> </html> ## functions.php /*------------------- enqueue scripts -------------------*/ add_action( 'wp_enqueue_scripts', 'techblog_scripts' ); function techblog_scripts() { //add icon with Google Material Icons wp_enqueue_style( 'google-mateial-style', "https://fonts.googleapis.com/icon?family=Material+Icons", null); //------omitted------ } ## Functions ### date_i18n() This function retrieves the date in localized format, based on a sum of Unix timestamp and time zone offset in seconds. It get format such as ‘Y-m-d H:i:s’, ‘l, F j, Y’ or ‘U’ as an argument. In this case, I’d like to retrieve year such as 2020. So I use template “Y”. date_i18n('Y') /*output is 2020)*/ ### esc_html() and esc_url() Escape functions in WordPress. Please check the article “Escape function in WordPress” for detail. ### home_url() This function retrieves the URL for the current site. ## How to use icons with Google Material Icon I used navigation icon in Google Material for the button to scroll to the top. Search the icon , copy and paste the span tag. Enqueue the css by using wp_enqueue_style() in functions.php wp_enqueue_style( 'google-mateial-style', "https://fonts.googleapis.com/icon?family=Material+Icons", null); You can use web icon service such as Font Awesome or Foundation Icon Fonts 3 in the same way. ## Result ## Change the style ## Create header.php for original theme This is one of the articles about project “Create Original Theme in WordPress”. ## GOAL To create header.php ## Environment WordPress 5.5.1 XAMPP 7.4.10 ## What content should be contained? These are examples of contents in the header. • Title • Description • Menu ## hader.php <?php /* * * The Header for techblog. *@package WordPress *@subpackage Techblog *@since Techblog 1.0 */ ?> <!doctype html> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <?php wp_head(); ?> </head> <body <?php body_class(); ?>> <?php wp_body_open(); ?> <header class="site-header"> <a class="skip-link" href="#content"><?php esc_html_e( 'Skip to content', 'techblog' ); ?></a> <div class="header-main"> <h1 class="site-title"> <?php if (has_custom_logo()): the_custom_logo(); else : ?> <a class="title-link" href="<?php echo esc_url( home_url( '/' ) ); ?>" title="<?php echo esc_attr(get_bloginfo('name'));?>"><?php echo esc_html(get_bloginfo('name'));?></a> <?php endif; ?> <span class="site-description"> <?php echo esc_html(get_bloginfo('description'));?> </span> </h1> <?php wp_nav_menu( array( 'menu' => '', 'theme_location' => '', 'container' => 'div', 'container_class' => 'manubar', 'menu_class' => 'nav', 'fallback_cb' => 'wp_page_menu', 'items_wrap' => '<ul id="%1$s" class="%2$s">%3$s</ul>',
)
); ?>
</div>
</header>

## functions.php

/*-------------------
enqueue scripts
-------------------*/
add_action( 'wp_enqueue_scripts', 'techblog_scripts' );
function techblog_scripts() {
// Add main theme stylesheet
wp_enqueue_style( 'techblog-main-style', get_stylesheet_uri(), null);
}

## Functions

The function wp_head() should be in <head></head>. This is initially the same as do_action(‘wp_head’).

function wp_head() {
/**
* Prints scripts or data in the head tag on the front end.
*
* @since 1.5.0
*/
}

This function fire functions attached to the hook ‘wp_head’. For example, some functions are added to the hook ‘wp_head’ in wordpress\wp-includes\default-filters.php as below.

// Actions.
...

Please check “What is Hook in WordPress?” for details about hooks in WordPress.

### body_class()

The function body_class() is displays the class names for the body element.

function body_class( $class = '' ) { // Separates class names with a single space, collates class names for body element. echo 'class="' . esc_attr( implode( ' ', get_body_class($class ) ) ) . '"';
}

The following is an example of actual HTML output.

<body class="home blog logged-in admin-bar no-customize-support">

### wp_body_open()

This function is initially the same as do_action(‘wp_body_open’).

function wp_body_open() {
/**
* Triggered after the opening body tag.
*
* @since 5.2.0
*/
do_action( 'wp_body_open' );
}

#### wp_nav_menu(array \$args = array())

wp_nav_menu() is the function to display navigation menu. the arguments list can be seen here.

### How to import style.css in the header

It is recommended to use wp_enqueue_scripts instead of embedding <link rel=”stylesheet” href=”wordpress/wp-content/themes/techblog/style.css” type=”text/css”/> in header.php directly.

Add add_action( ‘wp_enqueue_scripts’, ‘<enque_function_name>‘ ); in functions.php of your theme.

add_action( 'wp_enqueue_scripts', 'techblog_scripts' );
function techblog_scripts() {
// Add main theme stylesheet
wp_enqueue_style( 'techblog-main-style', get_stylesheet_uri(), null);
}