php 删除某个字符串逗号点前面的字符串

<?php

 
header('content-type:text/html;charset=utf-8');  

$str = "bbb.xx.com";
 
echo "原字符串：";
 
var_dump($str);
 
$start=stripos($str,".");
 
$newStr=substr($str, $start);

 
echo "去掉字符串的第一个点字符后：";
 
var_dump($newStr);
 
?>