Building efficient websites with AJAX
JavaScript
In contrast, JavaScript is not restricted to isolated areas of the web page. The interpreter that is integrated with the browser executes the program and converts the whole page into a dynamically modifiable interface. To do so, scripts create or modify the HTML code on the page, modify the cascading style sheet (CSS) styles, or even draw graphics.
The scripts themselves comprise uncompiled text. In contrast to Flash development, programming in JavaScript does not require any special tools. A simple text editor is fine for a start.
Good Tools
As always, good tools make programming easier. An editor with HTML, CSS, and JavaScript support is useful. It should also be able to handle source code that mixes all three [1][2]. Chris Pederick's Firefox plugin Web Developer [3] is the obvious choice for tracing and debugging programs. It reveals bugs in HTML, CSS, and JavaScript; investigates cookies; and displays the dynamically modified HTML code, not just the original version delivered by the server.
Tables
An increasing number of applications, such as order processing and enterprise resource planning (ERP) systems use web front ends: Parts lists or other list-type overviews are the main fare.
One important feature is the user's ability to sort these lists. If the web front end is based on static HTML, the server has to regenerate the page and serve up the modified version. Of course, client-side JavaScript-based data sorting makes for a smoother process.
Figure 2 gives an example of a directory listing implemented as an HTML table. Clicking the table header sorts the table by the current column. Figure 3 shows how to do this with JavaScript. An HTML table comprises nested <tr> and <td> elements, which can be addressed via DOM [4].
The script starts by dynamically removing all the <tr> elements (i.e., the rows in the table) from the page. The rows only exist as an array in JavaScript. The JavaScript function then sorts the array on the requested column and writes the new sorting order between the empty <table> and </table> tags. Finally, the script draws an arrow, a Unicode arrow [5] character, before the label of the column on which the table is sorted.
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you've found an article to be beneficial.
News
-
The GNU Project Celebrates Its 40th Birthday
September 27 marks the 40th anniversary of the GNU Project, and it was celebrated with a hacker meeting in Biel/Bienne, Switzerland.
-
Linux Kernel Reducing Long-Term Support
LTS support for the Linux kernel is about to undergo some serious changes that will have a considerable impact on the future.
-
Fedora 39 Beta Now Available for Testing
For fans and users of Fedora Linux, the first beta of release 39 is now available, which is a minor upgrade but does include GNOME 45.
-
Fedora Linux 40 to Drop X11 for KDE Plasma
When Fedora 40 arrives in 2024, there will be a few big changes coming, especially for the KDE Plasma option.
-
Real-Time Ubuntu Available in AWS Marketplace
Anyone looking for a Linux distribution for real-time processing could do a whole lot worse than Real-Time Ubuntu.
-
KSMBD Finally Reaches a Stable State
For those who've been looking forward to the first release of KSMBD, after two years it's no longer considered experimental.
-
Nitrux 3.0.0 Has Been Released
The latest version of Nitrux brings plenty of innovation and fresh apps to the table.
-
Linux From Scratch 12.0 Now Available
If you're looking to roll your own Linux distribution, the latest version of Linux From Scratch is now available with plenty of updates.
-
Linux Kernel 6.5 Has Been Released
The newest Linux kernel, version 6.5, now includes initial support for two very exciting features.
-
UbuntuDDE 23.04 Now Available
A new version of the UbuntuDDE remix has finally arrived with all the updates from the Deepin desktop and everything that comes with the Ubuntu 23.04 base.