php验证手机号码

1 function is_telephone($phone){
2 $chars = "/^13[0-9]{1}[0-9]{8}$|15[0-9]{1}[0-9]{8}$|18[0-9]{1}[0-9]{8}$/";
3 if (preg_match($chars, $phone)){
4 return true;
5 }
6 }