Question: If page has .pdf files linked then a message in `<p>` should be add just before end of the `#mainontent` div as a last paragraph `<p>` 

for example this is default html?

```
<div id="maincontent">
<ul class="cheat_sheet_downloads">
<li><a href="http://www.addedbytes.com/download/css-cheat-sheet-v2.pdf">PDF, 316Kb</a></li>
<li><a href="http://www.addedbytes.com/download/css-cheat-sheet-v3.pdf/">PNG, 77Kb</a></li>
</ul>
<div>

```

After detecting pdf

it should be like this

```
<div id="maincontent">
    <ul class="cheat_sheet_downloads">
    <li><a href="http://www.addedbytes.com/download/css-cheat-sheet-v2.pdf/">PDF, 316Kb</a></li>
    <li><a href="http://www.addedbytes.com/download/css-cheat-sheet-v3.pdf/">PNG, 77Kb</a></li>
    </ul>
<div>

<div id="ttip">
Most computers will open PDF documents automatically, but you may need to 
download <a title="Link to Adobe website - opens in a new window"  
href="http://www.adobe.com/products/acrobat/readstep2.html" target="_blank">
                 Adobe Reader</a>.
</div>

```

or as another div after `#maincontent` div. Is it possible with jquery?

Edit:

Page can have one or more PDF i want to add message at bottom. and i need IE 6 compatibility too

Edit 2 : I can't and don't want to use mouse over tooltip

Answer: 
I would say use `void *` so you can re-use the code. It's more work to re-implement e.g. a linked list, than to make sure you get/set the data in the list properly.

Take as many hints from [glib](http://library.gnome.org/devel/glib/stable/) as possible, I find their data structures very nice and easy to use, and have had little trouble because of the loss of type safety.
You can efficiently add type information, inheritance and polymorphism to C data structures, that's what C++ does. (<http://www.embedded.com/97/fe29712.htm>)