以下是常用的PHP函数，大家可以参考！
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=>..<<</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.]&&].$string.]‘ title=>>>..</a>];
if($page<>$totalpage)
$out .= [ <a href=’?page=].$totalpage.]&&].$string.]‘ title=最后页>最后页</a>];
return $out;
}
?>