php 输出最近三个月的日历

function week()
{
    $start='2013-11-01';
    $end = '2014-01-31';
    $arr = array();
    $c = (strtotime($end)-strtotime($start))/86400;
    for($i=0;$i<=$c;$i++){
        $d = strtotime($start)+(86400*$i);
        $arr[] = array(
            'd'=>date('d',$d),
            'w'=>date('w',$d),
            's'=>$d
        );
    }
    foreach ($arr as $k=>$a){
        if($k==0){
            for($i=1;$i<$arr[$k]['w'];$i++){
                echo '   ';
            }
        }
        echo $a['d'].' ';
        if($a['w']==0){
            echo '<br>';
        }
    }

}
//该片段来自于http://outofmemory.cn