My situation was as follows: Imagine a store. Every product has a unique identification code (NASA-number), a product description and a price, to keep it very basic. Then, every product has a stock number (The amount of items currently in stock). We're keeping these values apart from eachother because keeping the amount of items in stock isn't enough. We also need to keep a log of everything that happens to the product (how many do we sell per day, how many are delivered to us, how much do we throw out).

So basically, we have two tables. One contains all product information, and the second keeps daily logs of what happens to each and every product. Let's give you a basic table layout:

CREATE TABLE `nasa` (
`nasa` INT(16) NOT NULL,
`name` VARCHAR(255) NOT NULL,
`price` FLOAT NOT NULL,
`content` VARCHAR(255) NOT NULL,
UNIQUE KEY `nasa` (`nasa`)
);

This is the listing of the products, every single item has a unique NASA-number, names can overlap providing the content is different (think a litre of whole milk vs. a gallon of whole milk), than we have the log:

CREATE TABLE `history` (
`DAY` INT(16) NOT NULL,
`nasa` INT(16) NOT NULL,
`stock` INT(16) NOT NULL,
`received` INT(16) NOT NULL,
`sold` INT(16) NOT NULL,
`counted` INT(16) NOT NULL
);

So this one has a daily log. But if you want to display the data of these tables on your screen, you might be tempted to run two queries, one to fetch the name (for legibility, people aren't very likely to remember numbers), maybe the content and one to fetch the current stock (are we out? did we receive anything?). This would go as follows

SELECT name,content FROM nasa WHERE nasa=62334

and then

SELECT stock FROM history WHERE nasa=62334

What if you combined these two into a single query? First write down which things you need: name, content, sales and current stock. Then, lo and behold the power of the JOIN-statement.

SELECT name,content,stock,sold FROM nasa JOIN history ON nasa.nasa =
  history.nasa WHERE history.nasa = 62334 AND history.DAY = today

See that? You can just select the four columns you need. MySQL will retrieve any row where the history.nasa matches the nasa.nasa so be sure to specify which row you want to retrieve. In this case you could also order descending by the date and limit the rows retrieved to 1:

SELECT name,content,stock,sold FROM nasa JOIN history ON nasa.nasa =
  history.nasa WHERE history.nasa = 62334 ORDER BY history.DAY DESC LIMIT 1

Thanks for reading, hope it makes any sense :))

P.S. In case you were wondering, 62334 is an actual NASA number used in Albert Heijn. It's the code for fresh cod filet.

A theme generator, which takes in regular templates (all HTML), and turns them into a 'basic' template, with a widget-ready sidebar, archive support, comments, and what not!

Click

Please let me know what you think in the comments section. And, please; Do note that this is a beta version, hmm let's make up a number. Let's call it version Oh-point-six ?

Thanks for reading.

Here's a quick explanation:

 
<a href="#">Link text<span>Your tooltip</span></a>

Use that HTML. Then add the following to your stylesheet:

 
a { position: relative; outline: none; }
a span { display: none; }
a:hover span {
display: block;
font-size: 8pt;
position: absolute;
top:-25px; left: -45px;
border:1px solid #383a47;
background-color:#5cbbe3;
color: #383a47;
text-align: center;
padding: 1px 5px;
width: 130px; }

This code hides the span tag when you're not hovering over it. (a span { display: none; }) and positions it nicely when you DO hover over it.
Read on for an example (just a single hyperlink, but it's not valid xhtml so I put it on a different page)

Hover over me!Wow, a tooltip!

 
.clear { clear: both; }

This forces any item with a class of clear to be clear of floats on the left and right, which are - by chance - the other two options to clear; left and right. So after floating elements left and right, you should add a to force content below.

That little gem right there'll take any length of text and turn the urls in it into hyperlinks. Cool or what? :-)

You've probably heard of AJAX. It's an acronym for "Asynchronous Javascript And XML". It basically means you could use Javascript for updating a page, submitting info without refreshing and so forth. I've only just found out the basics of AJAX myself. It's not hard, but it requires (very) basic understanding of Javascript and HTML.

The biggest part about using AJAX is understanding the XMLHttpRequest() object. This object has a wide range of properties, functions and what not. But for basic AJAX you'll only need a couple.

Initializing the XMLHttpRequest object

 
function GetXML() {
var xmlHttp;
try
{
// Firefox, Opera 8.0+, Safari
xmlHttp=new XMLHttpRequest();
}
catch (e)
{
// Internet Explorer
try
{
xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e)
{
try
{
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
}
catch (e)
{
alert("Your browser does not support AJAX!");
}
}
}
return xmlHttp;
}

That is the function I'm using to get the object. Usually you could just use the XMLHttpRequest(), but since the (oh-so-loved) Internet Explorer doesn't support it. You need to make a complete function and have it return the object.

You can now use:

 
ajax = getXML();

to get the object instantiated.

Sending information

Okay, having this object is all nice and dandy, but we might want to use it and send info to other pages and retrieve the information. This is done as follows:

 
ajax.open(STRING method, STRING url, BOOL asynchronous);

So if we (e.g.) wanted to submit a star-rating for a specific id, we would want to pass on the id and the actual rating:

 
ajax.open("GET", "save_rating.php?id=WUT&rating="+rating,true)

Now Ajax has cached our request, ready to be sent:

 
ajax.send();

Ajax is now sending the request and receiving some information for itself and we might want to do something with the information we received.

Receiving information

Sending and receiving sound like a logical order here, but while using AJAX you might want to declare your ajax handler, and then immediately setup a function to handle the incoming traffic. Since AJAX uses functions to receive it:

 
ajax.onreadystatechange=function()
{
// On ready state change (Loading, Finished Loading.. etc)
//0    The request is not initialized
//1    The request has been set up
//2    The request has been sent
//3    The request is in process
//4    The request is complete
if(ajax.readyState==4)
{
// Received information.
document.getElementById('rating').innerHTML=ajax.responseText;
}
}

Woot. The only vital part here is ajax.responseText. And noticing you're passing a function to the ajax.onreadystatechange.

That's all for now, I'll write a tutorial about the star-rating system I've coded probably monday since I've got work tomorrow :(.

Thanks for reading!

Just wanted to share ;)

• Animated GIFs
  Animated GIFs are soo 1990's. I remember using them on my geocities website! And that, my dear reader, is almost prehistorical.
• Slow download times
  Nothing makes me stop browsing a website as slow load times. Waiting for the server to respond, takes up valuable time of your reader. Nobody likes waiting.

• Unreadable text
  Like.. Low contrast with the background: this, impossible colour combinations or a background that distracts too much from the content
• Blink & Marquee
  BLINK is EVIL. And Marquee is outdated. And they're annoying. Your turn.
• Looonngg pages
  Ever been on a site that loads for ages? And you just watch your little scrollbar getting smaller by the second. And when it finally finishes loading, you pick up your microscope and find that all that is left of your scrollbar are five nanometers. Lots of content is good, just organise it well, make pages.
• Under Construction
  If it's under construction, why do you even have a website? If it's not ready, don't list it. Simple as that.
• Background Sound
  I once was in the U.S.A, in a museum, and they had computers you could use for browsing the internet. I opened up a page, and to my horror, the volume was set to max and everyone in the museum heard it. It was really lousy music, too. That is just one reason not to use background music
• Designed for a specific browser / resolution / colour setting
  With such a variety of browsers around, why would you design your site to only work in (e.g) Internet Explorer. (bad example). This is killing your visits.
• Spelling/grammar mistakes
  Nothing looks as unprofessional as having spelling and/or grammar mistakes all over your website. Personally, as soon as the spelling/grammar looks really bad, I'm out - There's plenty more websites on the internet.
• Tables for layout
  Again: Sooo 1990's. DIVs styled with CSS are the norm now!
• Status bar text
  Ancient. Annoying.
• Too much images
  Lowering your loading speed, having a lot of gaps all over your website while it's loading. Not my favorite.
• Bad content
  Content is what the people come to your site for. Bad content and they're off again to google or wikipedia. Another visit lost.
• Hard to navigate
  If I can't find how to get to your (e.g) tutorials section, why would I stick around and look for it? If you cant even design your site with the user in mind, I might as well find someone who can do that. And probably write better tutorials too!
• Frames
  Frames can be good, but only if you know how to use them

And lastly, if you're writing a personal blog. Nobody cares, really. If you're just writing about yourself and nothing else, you're bound to lose visitors. Unless you have a strong sense of humour and are a good writer.