/**

随机生成字符串
*/
function randCode($length=5,$type=0){
$arr = array(1 => "0123456789", 2 => "abcdefghijklmnopqrstuvwxyz", 3 => "ABCDEFGHIJKLMNOPQRSTUVWXYZ", 4 => "~@#$%^&
(){}[]|");
if ($type == 0){
array_pop($arr);
$string = implode("", $arr);
}elseif($type == "-1"){
$string = implode("", $arr);
}else{
$string = $arr[$type];
}
$count = strlen($string) - 1;
$code = '';
for($i = 0; $i < $length; $i++){
$code .= $string[rand(0, $count)];
}
return $code;
}