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 count($temp);$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=" html head ";

if(!empty($url))

$html .=" meta http-equiv=@#refresh@# content=\"3;url=@#".$url."@#\" ";

$html .=" link href=@#../templates/style.css@# type=text/css rel=stylesheet ";

$html .=" /head body br br br br ";

$html .=" table cellspacing=@#0@# cellpadding=@#0@# border=@#1@# width=@#450@# align=@#center@# ";

$html .=" tr td bgcolor=@##ffffff@# ";

$html .=" table border=@#1@# cellspacing=@#1@# cellpadding=@#4@# width=@#100%@# ";

$html .=" tr class=@#m_title@# ";

$html .=" td ".$title." /td /tr ";

$html .=" tr class=@#line_1@# td align=@#center@# height=@#60@# ";

$html .=" br ".$message." br br ";

if (!empty($url))

$html .="系统将在3秒后返回 br 如果您的浏览器不能自动返回,请点击[ a href=".$url." target=_self 这里 /a ]进入";

else

$html .="[ a href=@##@# onclick=@#history.go(-1)@# 返回 /a ]";

$html .=" /td /tr /table /td /tr /table ";

$html .=" /body /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;

$out="共 font color=@#red@# b ".$totalpage." /b /font 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;

$prestart=$start-1;

$nextend=$end+1;

if($page 1)

$out .= " a href=@#?page=1&&".$string."@#title=第一页 第一页 /a ";

if($start 1)

$out.=" a href=@#?page=".$prestart."@# title=上一页 .. /a ";

for($t=$start;$t =$end;$t++)

{

$out .= ($page==$t) ? " font color=@#red@# b [".$t."] /b /font " : " a href=@#?page=$t&&".$string."@# $t /a ";

}

if($end $totalpage)

$out.=" a href=@#?page=".$nextend."&&".$string."@# title=下一页 .. /a ";

if($page $totalpage)

$out .= " a href=@#?page=".$totalpage."&&".$string."@# title=最后页 最后页 /a ";

return $out;

}



8.获取新插入数据的id

mysql_insert_id();

?