WordPres对前端页面调试时的两个PHP函数使用小技巧，_PHP教程

<input type="text" value="<&#63;php echo esc_attr( $instance['input_text'] ); &#63;>" id="subbox" onfocus="if ( this.value == '<&#63;php echo esc_js( $instance['input_text'] ); &#63;>') { this.value = ''; }" onblur="if ( this.value == '' ) { this.value = '<&#63;php echo esc_js( $instance['input_text'] ); &#63;>'; }" name="email" />

nocache_headers();

function Bing_add_ajax(){
  nocache_headers();
  echo true;
  die;
}
add_action( 'template_redirect', 'Bing_add_ajax' );