详解WordPress开发中wp_title()函数的用法

/
  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 mon 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 patibility of themes is
  important.
 
  @since 1.0.0
 
  @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 $seplocation Optional. Direction to display title, 'right'.
  @return string|null String on retrieve, null when displaying.
 /
function wp_title($sep = '»', $display = true, $seplocation = '') {
global $wpdb, $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_TITILE_SEP%'; // Temporary separator, for aurate 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 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();
 $tax = get_taxonomy( $term->taxonomy );
 $title = single_term_title( $tax->labels->name . $t_sep, false );
}
 
// If there's an author
if ( is_author() ) {
 $author = get_queried_object();
 $title = $author->display_name;
}
 
// If there's a post type archive
if ( is_post_type_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 ";
 
// Determines position of the separator and direction of the breadcrumb
if ( 'right' == $seplocation ) { // sep on right, so reverse the order
$title_array = explode( $t_sep, $title );
$title_array = array_reverse( $title_array );
$title = implode( " $sep ", $title_array ) . $prefix;
} else {
 $title_array = explode( $t_sep, $title );
 $title = $prefix . implode( " $sep ", $title_array );
}
 
$title = apply_filters('wp_title', $title, $sep, $seplocation);
 
// Send it out
 if ( $display )
 echo $title;
 else
 return $title;
 
}

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