background preloader

Tutorials and Tips

Facebook Twitter

IP address geolocation SQL database. CSS2/DOM - Styling an input type="file". Page last changed today Credits wholly go to Michael McGrady, who invented this technique.

CSS2/DOM - Styling an input type="file"

A browser must support opacity to support this technique. Therefore it doesn't work in Explorer 5.0 on Windows, Explorer 5 on Mac and Opera. A reader suggested adding a keyup event to the real input box so that you can copy the text the user types to the fake one. This page has been translated into Chinese and Italian. Of all form fields, the file upload field is by far the worst when it comes to styling. For a site I created I needed input fields like this one: The designer wanted the same styles, plus a "Select" image, to apply to all file upload fields.

Ponder the differences. Screenshot: File input fields in the various browsers This is hardly what anyone would call a nicely designed form field. Also note Safari's fundamentally different approach. Fortunately, reader Michael McGrady invented a very neat trick that allows us to (more or less) style file upload fields. CoLinux-APN1-e.pdf (application/pdf Object) Alan deLevie - Recursion-less storage of hierarchical data in a relational database.

One of the main problems with using a relational database such as MySQL is that it can be tricky to store and retrieve hierarchical information.

Alan deLevie - Recursion-less storage of hierarchical data in a relational database

Hierarchies are expressed with tree structures whereas relational databases use flat tables. So how can one fit this square peg into a round hole? Fortunately, there are several methods out there. Unfortunately most of these methods rely on recursion for either populating, updating, or deleting parts of tree. Check out this evolt article to learn more about the pitfalls of recursion (and even more ways to store hierarchical data). Storing Hierarchical Data in a Database. This article was written in 2003 and remains one of our most popular posts.

Storing Hierarchical Data in a Database

If you’re keen to learn more about mastering database management, you may find this recent article on MySQL of great interest. Whether you want to build your own forum, publish the messages from a mailing list on your Website, or write your own cms: there will be a moment that you’ll want to store hierarchical data in a database. And, unless you’re using a XML-like database, tables aren’t hierarchical; they’re just a flat list. You’ll have to find a way to translate the hierarchy in a flat file. Storing trees is a common problem, with multiple solutions. In this article, we’ll explore these two methods of saving hierarchical data.

This article contains a number of code examples that show how to save and retrieve data. The first, and most elegant, approach we’ll try is called the ‘adjacency list model’ or the ‘recursion method’. As you can see, in the adjacency list method, you save the ‘parent’ of each node. <? <? Send HTTP request as fast as possible. HTTP Request performance for large volumes of requests. Analysis of HTTP Performance Problems. Abstract This paper is the first in a series on performance issues in the World Wide Web.

Analysis of HTTP Performance Problems

HTTP is a transfer protocol used by the World Wide Web distributed hypermedia system to retrieve distributed objects. HTTP uses TCP as a transport layer. Certain design features of HTTP interact badly with TCP, causing problems with performance and with server scalability. Latency problems are caused by opening a single connection per request, through connection setup and slow-start costs. Summary of HTTP/1.0 HTTP [http] is a transfer protocol used by the World Wide Web to retrieve information from distributed servers. Requests The request format for HTTP is quite simple. The client can also send a series of optional headers; these headers are in RFC-822 format. Request syntax Example GET /index.html HTTP/1.0 Accept: text/plain Accept: text/html Accept: */* User-Agent: Yet Another User Agent Responses The response format is also quite simple.

The server now sends any requested data. Response syntax. C++, Development Tools, Java, Open Source, Web... the world of software development from Dr Dobb's. Joao Paulo Figueira - Professional Profile.