This is a frequently used PHP function.

1. generate random string functions

Function random ($ length ){
$ Hash = ";
$ Chars = 'abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxy ';
$ Max = strlen ($ chars)-1;
Mt_srand (double) microtime () * 1000000 );
For ($ I = 0; $ I <$ length; $ I ++ ){
$ Hash. = $ chars [mt_rand (0, $ max)];
}
Return $ hash;
}

2. truncate a string of a certain length

Note: This function is valid for GB2312.

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. Obtain the Client IP Address

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. Create a folder

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. Determine the email address

Function checkEmail ($ inAddress)
{
Return (ereg ("^ ([a-zA-Z0-9 _-]) + @ ([a-zA-Z0-9 _-]) + (. [a-zA-Z0-9 _-]) +", $ inAddress ));

}

6. Jump

Function gotourl ($ message = ", $ url =", $ title = ")
{

$ Html = "If (! Empty ($ url ))
$ Html. = "<meta http-equiv = 'refresh' content =" 3; url = '". $ url."' "> ";
$ Html. = "<link href = '../templates/style.css' type = text/css rel = stylesheet> ";
$ Html. = "$ Html. = "<table cellspacing = '0' cellpadding = '0' border = '1' width = '000000' align = 'center'> ";
$ Html. = "<tr> <td bgcolor = '# ffff'> ";
$ Html. = "<table border = '1' cellspacing = '1' cellpadding = '4' width = '000000'> ";
$ Html. = "<tr class ='m _ title'> ";
$ Html. = "<td>". $ title. "</td> </tr> ";
$ Html. = "<tr class = 'line _ 1'> <td align = 'center' height = '60'> ";
$ Html. = "<br>". $ message. "<br> ";
If (! Empty ($ url ))
$ Html. = "the system will return in 3 seconds <br> If your browser cannot return automatically, click [<a href = ". $ url. "target = _ self> here </a>] Enter ";
Else
$ Html. = "[<a href = # onclick = history. go (-1)> return </a>]";
$ Html. = "</td> </tr> </table> ";
$ Html. = "</body> Echo $ html;
Exit;
}

7. Paging (two functions are used together)

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 = "total <font color = 'red'> <B>". $ totalpage. "</B> </font> page & nbsp ;";
$ 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 = first page> first page </a> & nbsp ;";
If ($ start> 1)
$ Out. = "<a href = '? Page = ". $ prestart." 'title =>... </a> & nbsp ;";
For ($ t = $ start; $ t <= $ end; $ t ++)
{
$ Out. = ($ page = $ t )? "<Font color = 'red'> <B> [". $ t. "] </B> </font> & nbsp;": "<a href = '? Page = $ t & ". $ string." '> $ t </a> & nbsp ;";
}
If ($ end <$ totalpage)
$ Out. = "<a href = '? Page = ". $ nextend." & ". $ string." 'title = >>>... </a> ";
If ($ page <> $ totalpage)
$ Out. = "& nbsp; <a href = '? Page = ". $ totalpage." & ". $ string." 'title = last page> last page </a> ";
Return $ out;
}

?>