//-- Get all request string key/value pairs
$s = $_REQUEST;
if($s['key'] == 'tags'){
return $s['tag'];
} else {
return false;
}<h1>[[!dyntagtitle:notempty=`Posts Tagged with "[[!dyntagtitle]]"`:empty=`[[*longtitle:empty=`[[*pagetitle]]`]]`]]</h1>

<h1>[[+arc_year:notempty=`[[+arc_month_name]] [[+arc_year]]`:empty=`[[*longtitle:empty=`[[*pagetitle]]`]]</h1>
[[+arc_year]]
<?php
$output='';
$get = $modx->sanitize($_GET);
if (ISSET($get['tag'])){
$tag=urldecode($get['tag']);
$output='Articles tagged \''.$tag.'\'';
}
if (ISSET($get['arc_year'])){
$output='Articles posted during '.date( 'F', mktime(0, 0, 0, $get['arc_month'])).' '.$get['arc_year'];
}
if ($output!=''){
$modx->setPlaceholder('extratitle',' - '.$output);
$modx->setPlaceholder('extradescription',' '.$output);
$modx->setPlaceholder('extrah1','<h1>'.$output.'</h1>');
}
<?php
$output='';
$get = $modx->sanitize($_GET);
if (ISSET($get['tag'])){
$tag=urldecode($get['tag']);
$output='Articles tagged \''.$tag.'\'';
}
if (ISSET($get['arc_year'])){
$output='Articles posted during '.date( 'F', mktime(0, 0, 0, $get['arc_month'])).' '.$get['arc_year'];
}
if (ISSET($get['page'])){
$output.=' - page '.$get['page'];
}
if ($output!=''){
$modx->setPlaceholder('extratitle',' - '.$output);
$modx->setPlaceholder('extradescription',' '.$output);
$modx->setPlaceholder('extrah1','<h1>'.$output.'</h1>');
}
<?php
$output='';
$pagetitle = $modx->resource->get('pagetitle');
$get = $modx->sanitize($_GET);
if (ISSET($get['tag'])){
$tag=urldecode($get['tag']);
$output=$tag;
}
if (ISSET($get['arc_year'])){
$output='Articles posted during '.date( 'F', mktime(0, 0, 0, $get['arc_month'])).' '.$get['arc_year'];
}
if ($output!=''){
$modx->setPlaceholder('blogTitlePlain',' '.$output);
}
else {
$output = $pagetitle;
$modx->setPlaceholder('blogTitlePlain',' '.$output);
}
[[blogTitle]]
[[+blogTitlePlain]]
$default='My subheading goes here';
$pagetitle
$default
$default='My continuing adventures in astro-imaging, and astronomy in general';
$output='';
$pagetitle = $modx->resource->get('description');
$get = $modx->sanitize($_GET);
if (ISSET($get['tag'])){
$tag=urldecode($get['tag']);
$output='Articles posted with ' . $tag;
}
if (ISSET($get['arc_year'])){
$output='Articles posted in '.$get['arc_year'];
}
if (ISSET($get['arc_month'])){
$output='Articles posted during '.date( 'F', mktime(0, 0, 0, $get['arc_month'])).' '.$get['arc_year'];
}
if ($output!=''){
$modx->setPlaceholder('blogTitlePlain',' '.$output);
}
else {
$output = $default;
$modx->setPlaceholder('blogTitlePlain',' '.$output);
}