Below are some useful techniques for those who already know what they're doing.

Please visit my websites "Under One Roof".

Enjoy!

ps. if you find errors or have suggestions, please let me know.

"Week of Month" or "Occurence of Weekday" select statement.

MySQL does not have this built in function but this fairly complicated statement
is a work around. Typical use would be selecting the 3rd monday of the month.
Displayed with "SET" for clarity.

Versions lower than 4.1:
SET @d = '2007-09-30'; SET @x = DAYOFMONTH(@d); SET @y = DAYOFMONTH((DATE_FORMAT(@d,'%Y-%m-01')-INTERVAL 1 DAY)+INTERVAL 1 MONTH); SET @z = DAYOFWEEK(DATE_FORMAT(@d,'%Y-%m-01')); SELECT FLOOR(@x/(7+(7/((@y+1)-@z)))+1.03) as weekofmonth;

Versions 4.1 and above: (using LAST_DAY)
SET @d = '2007-09-30'; SET @x = DAYOFMONTH(@d); SET @y = DAYOFMONTH(LAST_DAY(@d)); SET @z = DAYOFWEEK(DATE_FORMAT(@d,'%Y-%m-01')); SELECT FLOOR(@x/(7+(7/((@y+1)-@z)))+1.03) as weekofmonth;

It works by applying the following formula:
SELECT FLOOR ( x / ( 7 + ( 7 / ( ( y + 1 ) - z ) ) ) + 1.03 );

Where:
d = date
x = day of month
y = days in month
z = 1st day of month
7 = days in a week

In a nutshell:
It basically divides the date by a week, calculating for incomplete weeks in the month.
Uses FLOOR and +1 instead of CEIL to prevent errors if zero.
Adds another .03 to correct for short months.

Shift images around to update form fields. Useful for administrative functions that modify sort order. Uses the awesome Script.aculo.us libraries.

Javascript: (in the head)
function updateOrder(divID,fldID) { var str = ""; var options = { parameters : Sortable.serialize(divID) }; var Sarray = new Array(); Sarray = options.parameters.split("&"); for (x=1; x<=Sarray.length; x++) { str = Sarray[x-1]; document.getElementById(fldID.concat(x)).value = str.substring((str.lastIndexOf('=')+1)); } }

HTML: (note incrementing field names)
<div id="divname"><input id="fname1" name="fname1" value="1" type="text" size="3" style="width:50px; font-size:10px"><input id="fname2" name="fname2" value="2" type="text" size="3" style="width:50px; font-size:10px"><input id="fname3" name="fname3" value="3" type="text" size="3" style="width:50px; font-size:10px"><input id="fname4" name="fname4" value="4" type="text" size="3" style="width:50px; font-size:10px"><input id="fname5" name="fname5" value="5" type="text" size="3" style="width:50px; font-size:10px"><input id="fname6" name="fname6" value="6" type="text" size="3" style="width:50px; font-size:10px"></div>

Javascript: (in the body after the above HTML)
<script type="text/javascript" language="javascript"> Sortable.create('divname', { tag:'img', overlap:'horizontal' ,constraint: false, onUpdate:function(){ updateOrder('divname','fname'); } }) // divname = ID enclosing draggable images // fname = field names constant </script>

Drag images to test

Here is a technique for retrieving data sans XMLHttpRequest. An AJAX workaround.

Javascript:
function dynamicdata() { var script_name = "http://www.domainname.com/cgi-bin/scriptname.cgi?field=value"; script_name += '&rand=' + Math.random(0,1000); //Safari cache patch var js_doc = document.getElementsByTagName('head').item(0); var js_cont = document.createElement('script'); js_cont.setAttribute('language','javascript'); js_cont.setAttribute('type','text/javascript'); js_cont.setAttribute('src',script_name); js_doc.appendChild(js_cont); }

Perl: (or other server-side scripting language)
#set variable print "document.form_name.field_name1.value='".$dynamicdata."';\n"; #modify text print "document.getElementById('poo').innerHTML='".$dynamicdata."';\n";

HTML:
<form name="form_name"><textarea name="field_name1" STYLE="width:30px; height:14px; background-color:#ccc; border: 1px solid; font-family: sans-serif; font-size:10px;" onClick="dynamicdata()"></textarea></form> <span id="poo">text</span>

non-AJAX method:	click to get time
AJAX method:	click to get time		(Mozilla Developer Center method)

Image preview before uploading:
Useful for admin functions. Your file path may be different.

Javascript:
document.getElementById('prev').innerHTML = '<img src="file://'+this.value+'" width="50" height="50" hspace="0" vspace="0" border="1">';

HTML:
<span id="prev"><img src="http://www.dogcollarlabor.com/IMAGES/spacer.gif" width="50" height="50" hspace="1" vspace="0" border="1"></span> <input name="filefield" type="file" onChange="preview('prev',this.value);">

Using the second of the year as a 9 digit unique identifier:
my $sec_of_year = sprintf(((localtime)[5]-100)."%03d%05d",(localtime)[7],((localtime)[2]*3600)+((localtime)[1]*60)+(localtime)[0]);

Example: 823366360

Parse the above identifier back to human readable:
use POSIX; use HTTP::Date; my $time = sprintf("%02d:%02d:%02d",floor((substr($sec_of_year,4,9)-0)/3600),floor(floor(substr($sec_of_year,4,9)%3600)/60),floor(substr($sec_of_year,4,9)%3600)%60); my $date_with_time = time2str(str2time((2000+(substr($sec_of_year,0,1))).'0101 '.$time,'+0000')+(86400*(substr($sec_of_year,1,3))));

Example: Thu, 21 Aug 2008 18:26:00 GMT

Extract sender from email using formail and pass to a Perl script: (then kill it)

.procmailrc recipe:
WHOTO=`formail -xTo: | expand | sed -e 's/\\@/\\\@/g'` WHOREPLY=`formail -xReply-To: | expand | sed -e 's/\\@/\\\@/g'` :0 H * (To:.*@domain\.com) { RESULT = `/home/user/cgi-bin/script.cgi "$WHOTO,$WHOREPLY"` :0 /dev/null }

Perl script:
$_ = $ARGV[0]; chomp; ($whoto,$whofrom) = split(/, /,$_);

"dupe" images directory for SSL access.

First:
Mirror the directory path to images directory inside the secure_html directory and place the following .htaccess file in it.

(ie. "/public_html/images/" = "/secure_html/images/").

Do not mirror the actual image files.

.htaccess code:
Options +FollowSymLinks RewriteEngine On RewriteRule ^(.*)\.jpg$ http://www.yourdomain.com/images/$1.jpg [NC,L]

Using an associative array instead of conditionals to "flip" a variable.

Javascript:
var image = 'back'; var pop = {'back':'front','front':'back'}; function flip() { alert('image: ' + pop[image]); image = pop[image]; }

test

Use a locally stored Javascript src file to write password information into your administration page. innerHTML & IDs might be more elegant

In the admin.js file stored locally on your computer.
var htpass = "user:pass"; //htaccess protected directory var login = new Array(); login["account"]="password"; //server login

In the head of your admin page: (the path to admin.js - yours will be different)
<script src="file://localhost/Users/Mac/Desktop/admin.js" type="text/javascript"></script>

In the body of your admin page: (Perl generated)
%website = ('account','www.test.com'); foreach (keys %website) { print "FTP: <SCRIPT LANGUAGE=\"JavaScript\">document.write(\"<a href=\\\"ftp://" . $_ . ":\"+login[\"" . $_ . "\"]+\"\@". $website{$_} . "\\\">" . $_ . "</a>\")</SCRIPT>"; print "<BR><BR>\n"; print "HTPROTECTED: <SCRIPT LANGUAGE=\"JavaScript\">document.write(\"<a href=\\\"http://\"+htpass+\"\@" . $website{$_} . "\\\">" . $_ . "</a>\")</SCRIPT>"; }

Informative MySQL errors: (email to admin)
die &subroutine(__FILE__,__LINE__,$mysql_command) unless (defined $sth);

Order string to hash:
$order = 'ABCDE12345_1-ABCDE12346_5'; %orderhash = split(/_/,join("_",split(/-/,$order)));

Print table columns:
$cols = 4; print "<table><tr>"; foreach $arr(0..27) { $cnt++; print "<td>$arr</td>"; if (abs($cnt - $cols * int($cnt / $cols)) == 0 && $cnt) { print "</tr><tr>\n"; } } print "</tr></table>";