一些使用频率较高的非常实用的PHP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   $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; $i    if(ord($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   $startpos = ($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))    $prestart=$start-1;
    $nextend=$end+1;
    if($page1)
 $out .= "第一页 ";
    if($start>1)
 $out.=".. ";
 for($t=$start;$t    {
     $out .= ($page==$t) ? "[".$t."] " : "$thref=@#?page=$t&&".$string."@#>$t ";
    }
 if($end $out.=">>..";
    if($page$totalpage)
   $out .= " 最后页";
   return $out;
}

8.获取新插入数据的ID

mysql_insert_id();
?>