这是一些使用频率比较高的函数......

1.产生随机字符串函数

function random($length) {
$hash = @#@#;
$chars = @#ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz@#;
$max = strlen($chars) - 1;
mt_srand((double)microtime() * 1000000);
for($i = 0; $i < $length; $i++) {
$hash .= $chars[mt_rand(0, $max)];
}
return $hash;
}

2.截取一定长度的字符串

注：该函数对GB2312使用有效

function wordscut($string, $length ,$sss=0) {
if(strlen($string) > $length) {
if($sss){
$length=$length - 3;
$addstr=@# ...@#;
}
for($i = 0; $i < $length; $i++) {
if(ord($string[$i]) > 127) {
$wordscut .= $string[$i].$string[$i + 1];
$i++;
} else {
$wordscut .= $string[$i];
}
}
return $wordscut.$addstr;
}
return $string;
}

3.取得客户端IP地址

function GetIP(){
if (getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown"))
$ip = getenv("HTTP_CLIENT_IP");
else if (getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown"))
$ip = getenv("HTTP_X_FORWARDED_FOR");
else if (getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown"))
$ip = getenv("REMOTE_ADDR");
else if (isset($_SERVER[@#REMOTE_ADDR@#]) && $_SERVER[@#REMOTE_ADDR@#] && strcasecmp($_SERVER[@#REMOTE_ADDR@#], "unknown"))
$ip = $_SERVER[@#REMOTE_ADDR@#];
else
$ip = "unknown";
return($ip);
}

4.创建相应的文件夹

function createdir($dir=@#@#)
{
if (!is_dir($dir))
{
$temp = explode(@#/@#,$dir);
$cur_dir = @#@#;
for($i=0;$i {
$cur_dir .= $temp[$i].@#/@#;
if (!is_dir($cur_dir))
{
@mkdir($cur_dir,0777);
}
}
}
}

5.判断邮箱地址

function checkEmail($inAddress)
{
return (ereg("^([a-zA-Z0-9_-])+@([a-zA-Z0-9_-])+(\.[a-zA-Z0-9_-])+",$inAddress));
}

6.跳转

function gotourl($message=@#@#,$url=@#@#,$title=@#@#)
{
$html ="";
if(!empty($url))
$html .="
";
$html .="";
$html .="



";
$html .="

";
$html .="

"; $html .=" "; $html .=" "; $html .=" "; $html .=" class=@#line_1@#> ".$title." "; $html .=" ".$message." "; if (!empty($url)) $html .="系统将在3秒后返回 如果您的浏览器不能自动返回,请点击[这里]进入"; else $html .="[返回]"; $html .="

";
$html .="";
echo $html;
exit;
}

7.分页（两个函数配合使用）

function getpage($sql,$page_size=20)
{
global $page,$totalpage,$sums; //out param
$page = $_GET["page"];
//$eachpage = $page_size;
$pagesql = strstr($sql," from ");
$pagesql = "select count(*) as ids ".$pagesql;
$result = mysql_query($pagesql);
if($rs = mysql_fetch_array($result)) $sums = $rs[0];
$totalpage = ceil($sums/$page_size);
if((!$page)||($page<1)) $page=1;
$startpos = ($page-1)*$page_size;
$sql .=" limit $startpos,$page_size ";
return $sql;
}
function showbar($string="")
{
global $page,$totalpage;
$out="共".$totalpage."color=@#red@#>".$totalpage."页 ";
$linkNum =4;
$start = ($page-round($linkNum/2))>0 ? ($page-round($linkNum/2)) : "1";
$end = ($page+round($linkNum/2))<$totalpage ? ($page+round($linkNum/2)) : $totalpage;
上一篇：教你用PHP写MySQL数据..start=$start-1;
$nextend=$end+1;
if($page<>1)
$out .= "第一页 ";
if($start>1)
$out.="..<< ";
for($t=$start;$t<=$end;$t++)
{
$out .= ($page==$t) ? "[".$t."]color=@#red@#>[".$t."] " : "$t ";
}
if($end<$totalpage)
$out.=">>..";
if($page<>$totalpage)
$out .= " 最后页";
return $out;
}

8.获取新插入数据的ID

mysql_insert_id();
?>