date("l"); //date就可以获取英文的星期比如Sunday
date("w"); //这个可以获取数字星期比如123，注意0是星期日
获取中文星期几：
$weekarray=array("日","一","二","三","四","五","六"); //先定义一个数组
echo "星期".$weekarray[date("w")];
获取指定日期是：
$weekarray=array("日","一","二","三","四","五","六");
echo "星期".$weekarray[date("w","2011-11-11")];