PHP生成随机字符串

函数：

function generateRandomString($length = 10)
{ 
    $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'; 
    $randomString = ''; 
    for ($i = 0; $i < $length; $i++)
	{ 
        $randomString .= $characters[rand(0, strlen($characters) - 1)]; 
    } 
    return $randomString; 
} 

使用方法：

echo generateRandomString(22);