wp_title( string $sep = '»', bool $display = true, string $seplocation = '' )

显示或检索博客所有区域的页面标题。
Display or retrieve page title for all areas of blog.

说明（Description）

默认情况下，页面标题将在页面标题之前显示分隔符，因此博客标题将位于页面标题之前。这不利于标题显示，因为博客标题显示在大多数选项卡上，而不是重要的内容，即用户正在查看的页面。也有搜索引擎优化的好处，有博客标题后或'右'的网页标题。然而，大多数浏览器都支持标签页，所以博客标题在右边是很正常的。您可以通过使用seplocation参数并将值设置为'right'来实现。这种变化是在2.5.0左右引入的，以防主题的向后兼容性很重要。

参数（Parameters）

源码（Source）

/**
 * Display or retrieve page title for all areas of blog.
 *
 * By default, the page title will display the separator before the page title,
 * so that the blog title will be before the page title. This is not good for
 * title display, since the blog title shows up on most tabs and not what is
 * important, which is the page that the user is looking at.
 *
 * There are also SEO benefits to having the blog title after or to the 'right'
 * or the page title. However, it is mostly common sense to have the blog title
 * to the right with most browsers supporting tabs. You can achieve this by
 * using the seplocation parameter and setting the value to 'right'. This change
 * was introduced around 2.5.0, in case backwards compatibility of themes is
 * important.
 *
 * @since 1.0.0
 *
 * @global WP_Locale $wp_locale
 * @global int       $page
 * @global int       $paged
 *
 * @param string $sep         Optional, default is '»'. How to separate the various items within the page title.
 * @param bool   $display     Optional, default is true. Whether to display or retrieve title.
 * @param string $seplocation Optional. Direction to display title, 'right'.
 * @return string|void String on retrieve.
 */
function wp_title( $sep = '»', $display = true, $seplocation = '' ) {
	global $wp_locale, $page, $paged;

	$m = get_query_var('m');
	$year = get_query_var('year');
	$monthnum = get_query_var('monthnum');
	$day = get_query_var('day');
	$search = get_query_var('s');
	$title = '';

	$t_sep = '%WP_TITILE_SEP%'; // Temporary separator, for accurate flipping, if necessary

	// If there is a post
	if ( is_single() || ( is_home() && !is_front_page() ) || ( is_page() && !is_front_page() ) ) {
		$title = single_post_title( '', false );
	}

	// If there's a post type archive
	if ( is_post_type_archive() ) {
		$post_type = get_query_var( 'post_type' );
		if ( is_array( $post_type ) )
			$post_type = reset( $post_type );
		$post_type_object = get_post_type_object( $post_type );
		if ( ! $post_type_object->has_archive )
			$title = post_type_archive_title( '', false );
	}

	// If there's a category or tag
	if ( is_category() || is_tag() ) {
		$title = single_term_title( '', false );
	}

	// If there's a taxonomy
	if ( is_tax() ) {
		$term = get_queried_object();
		if ( $term ) {
			$tax = get_taxonomy( $term->taxonomy );
			$title = single_term_title( $tax->labels->name . $t_sep, false );
		}
	}

	// If there's an author
	if ( is_author() && ! is_post_type_archive() ) {
		$author = get_queried_object();
		if ( $author )
			$title = $author->display_name;
	}

	// Post type archives with has_archive should override terms.
	if ( is_post_type_archive() && $post_type_object->has_archive )
		$title = post_type_archive_title( '', false );

	// If there's a month
	if ( is_archive() && !empty($m) ) {
		$my_year = substr($m, 0, 4);
		$my_month = $wp_locale->get_month(substr($m, 4, 2));
		$my_day = intval(substr($m, 6, 2));
		$title = $my_year . ( $my_month ? $t_sep . $my_month : '' ) . ( $my_day ? $t_sep . $my_day : '' );
	}

	// If there's a year
	if ( is_archive() && !empty($year) ) {
		$title = $year;
		if ( !empty($monthnum) )
			$title .= $t_sep . $wp_locale->get_month($monthnum);
		if ( !empty($day) )
			$title .= $t_sep . zeroise($day, 2);
	}

	// If it's a search
	if ( is_search() ) {
		/* translators: 1: separator, 2: search phrase */
		$title = sprintf(__('Search Results %1$s %2$s'), $t_sep, strip_tags($search));
	}

	// If it's a 404 page
	if ( is_404() ) {
		$title = __('Page not found');
	}

	$prefix = '';
	if ( !empty($title) )
		$prefix = " $sep ";

	/**
	 * Filter the parts of the page title.
	 *
	 * @since 4.0.0
	 *
	 * @param array $title_array Parts of the page title.
	 */
	$title_array = apply_filters( 'wp_title_parts', explode( $t_sep, $title ) );

 	// Determines position of the separator and direction of the breadcrumb
	if ( 'right' == $seplocation ) { // sep on right, so reverse the order
		$title_array = array_reverse( $title_array );
		$title = implode( " $sep ", $title_array ) . $prefix;
	} else {
		$title = $prefix . implode( " $sep ", $title_array );
	}

	if ( current_theme_supports( 'title-tag' ) && ! is_feed() ) {
		$title .= get_bloginfo( 'name', 'display' );

		$site_description = get_bloginfo( 'description', 'display' );
		if ( $site_description && ( is_home() || is_front_page() ) ) {
			$title .= " $sep $site_description";
		}

		if ( ( $paged >= 2 || $page >= 2 ) && ! is_404() ) {
			$title .= " $sep " . sprintf( __( 'Page %s' ), max( $paged, $page ) );
		}
	}

	/**
	 * Filter the text of the page title.
	 *
	 * @since 2.0.0
	 *
	 * @param string $title       Page title.
	 * @param string $sep         Title separator.
	 * @param string $seplocation Location of the separator (left or right).
	 */
	$title = apply_filters( 'wp_title', $title, $sep, $seplocation );

	// Send it out
	if ( $display )
		echo $title;
	else
		return $title;

}

笔记（Notes）