[TOC]
1. 手机验证码
```
//方法一:
function randString($len=6)
{
$chars = str_repeat('0123456789', 3);
// 位数过长重复字符串一定次数
$chars = str_repeat($chars, $len);
$chars = str_shuffle($chars);
$str = substr($chars, 0, $len);
return $str;
}
//方法二:
function randomKeys($length=6)
{
$key='';
$pattern='1234567890';
for($i=0;$i<$length;++$i)
{
$key .= $pattern{mt_rand(0,9)};
}
return $key;
}
//方法三:
function randomCaptcha(){
$randNumber=mt_rand(100000,999999);
str_shuffle($randNumber);
return $randNumber;
}
```
