関数の定義 <?php function calendar($year = '', $month = '') { if (empty($year) && empty($month)) { $year = date('Y'); $month = date('n'); } //月末の取得 $l_day = date('j', mktime(0, 0, 0, $month + 1, 0, $year)); //初期出力 $html = <<<EOM <table class="calendar"> <thead> <tr> <td colspan="2"> </td> <th colspan="3">{$year}年{$month}月</th> <td colspan="2"> </td> </tr> </thead> <tbody> <tr> <th class="sun">日</th> <t