<b>一些常用的php函数</b>

functionrandom($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

functionwordscut($string,$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

functionGetIP(){
if(getenv("HTTP_CLIENT_IP")&&strcasecmp(getenv("HTTP_CLIENT_IP"),"unknown"))
$ip=getenv("HTTP_CLIENT_IP");
elseif(getenv("HTTP_X_FORWARDED_FOR")&&strcasecmp(getenv("HTTP_X_FORWARDED_FOR"),"unknown"))
$ip=getenv("HTTP_X_FORWARDED_FOR");
elseif(getenv("REMOTE_ADDR")&&strcasecmp(getenv("REMOTE_ADDR"),"unknown"))
$ip=getenv("REMOTE_ADDR");
elseif(isset($_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

functioncreatedir($dir='')
{
if(!is_dir($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

functioncheckEmail($inAddress)
{
return(ereg("^([a-zA-Z0-9_-])+@([a-zA-Z0-9_-])+(.[a-zA-Z0-9_-])+",$inAddress));
}
?>

6.跳转

functiongotourl($message='',$url='',$title='')
{

$html="";
if(!empty($url))
$html.="";
$html.="";
$html.="

";
$html.="";
$html.="";
$html.="";
$html.="";
$html.="".$title."";
$html.="";
$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）

functiongetpage($sql,$page_size=20)
{
global$page,$totalpage,$sums;//outparam
$page=$_GET["page"];
//$eachpage=$page_size;
$pagesql=strstr($sql,"from");
$pagesql="selectcount(*)asids".$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;
}

functionshowbar($string="")
{
global$page,$totalpage;
$out="共".$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;
$prestart=$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."]":"$t";
}
if($end<$totalpage)
$out.=">>..";
if($page<>$totalpage)
$out.="最后页";
return$out;
}

?>