描述：

获取当前页面的标题

用法：

 <?php wp_title( $sep, $display, $seplocation ); ?> 

参数：

函数总是从数据库返回一个值，参数定义将什么信息附加到数据库值、附加到哪里以及如何格式化。

$sep

(string) (可选) 默认值为“？”。如何分隔页面标题中的各个项目。

默认值: » (»)

$display

(boolean) (可选) 将返回值格式化为文本（TRUE）或另一个PHP函数的参数（FALSE）。

默认值: TRUE

$seplocation

(string) (可选) 分隔符的位置（“左”或“右”）。

默认值: left

示例：

如果没有为单个帖子传递任何参数，例如：

 <title><?php wp_title(); ?></title>
//如果文章的标题是“Hello world！”，则函数将返回。
 » Hello world!

如果要更改标题在不同页面上的显示方式，可以使用筛选器。

/**
 * Filters wp_title to print a neat <title> tag based on what is being viewed.
 *
 * @param string $title Default title text for current view.
 * @param string $sep Optional separator.
 * @return string The filtered title.
 */
function theme_name_wp_title( $title, $sep ) {
	if ( is_feed() ) {
		return $title;
	}
	
	global $page, $paged;

	// Add the blog name
	$title .= get_bloginfo( 'name', 'display' );

	// Add the blog description for the home/front page.
	$site_description = get_bloginfo( 'description', 'display' );
	if ( $site_description && ( is_home() || is_front_page() ) ) {
		$title .= " $sep $site_description";
	}

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

	return $title;
}
add_filter( 'wp_title', 'theme_name_wp_title', 10, 2 );

源文件：

function wp_title( $sep = '»', $display = true, $seplocation = '' ) {
    global $wp_locale;
 
    $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_TITLE_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 query. */
        $title = sprintf( __( 'Search Results %1$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 ";
    }
 
    /**
     * Filters 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 );
    }
 
    /**
     * Filters 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;
    }
}