Technology Tales

Adventures & experiences in contemporary technology

Using external JavaScript files? Just don’t load them at the bottom of the page…

21st July 2007

Looking through Google Analytics for my websites, I have always been struck by the lack of IE7 uptake seemingly apparent from the statistics. However, I recently discovered that there may be a reason for this. I use the Ultimate GA plugin with my WordPress blogs and that adds the JavaScript code block near the bottom of the page. However, I recently saw that giving me scripting errors in IE7 and a spot of manual coding saw it travel to the header section of the web page. That, and the deactivation of the said plugin, was sufficient to rid of the errors in question. Seeing the effect of my changes on the reported share of visitors using IE7 could be interesting. It might even boost the Vista numbers as well.

An inappropriate use of JavaScript

3rd July 2007

I have seen a web application that displays thousands of records in a scrollable table (please bear with me, there is a very good reason for this). from the appearance of the table, it would be reasonable to assume that the table is generated by the server and output directly to the screen but this isn’t the case. What actually happens is that the server more or less outputs JavaScript code that is then executed. This takes the form of large arrays that are slotted into the DOM as the contents of the required table by a JavaScript function. With the large amounts of data involved, this means that the browser fully loads the client CPU while the JavaScript processing takes place, something that takes up to a minute to complete. Admittedly, the browser is IE6 but this was all on a PC with a 2.53 GHz Pentium 4 and 512 MB of memory. Getting the server to deliver standards-compliant (X)HTML for what is needed in the first place seems a much, much better approach to me.

IE6 and JavaScript performance

22nd June 2007

Having been exposed to an application at work that uses a lot of JavaScript, I fully appreciate what some mean when they talk about IE6’s inefficient handling of JavaScript. After seeing a web page taking an age to reload and your CPU taking a hammering because of JavaScript processing, the penny does tend to drop… Needless to say, this very much impacts the world of AJAX-driven web applications with their heavy dependence of client-side JavaScript. While IE7 does come to the rescue, there remain plenty of IE6 users still out there and this is reflect in website statistics. This reflects a certain level of inertia in the browser market that not only afflicts the uptake of IE7 but also the likes of Mozilla, Opera and Safari. It also means that anyone developing AJAX applications very much needs to continue testing in IE6, especially if the product of their labours is for wider public use. An example of such an application is Zimbra, an open source web application for messaging and collaboration, and the people behind it have generously share the results of their browser performance benchmarking. They did comparisons of IE6 vs. IE7 and Firefox 2 vs. IE7. IE6 easily came out as the worst in these while Firefox 2 was the best. I suppose that the next question to be asked centres around the type of code that is processed inefficiently by IE6. I wouldn’t be at all surprised if a list emerged but here’s one: using Microsoft’s proprietary innerHTML object to update the DOM for a web page format. Having a quick trawl on Google, this came up for mention as a cause of memory leaks. It is also a Microsoft innovation that never got taken up by those overseeing web standards, hardly a surprise since a spot of DOM scripting achieves the same end. It may be faster to code than any alternatives, and it does have some support from other browsers, but it does seem to have got a bad name and so should be avoided if possible. That said, it would be interesting to see a performance comparsion between innerHTML and DOM methods in IE6.

Perl vs. PHP: A Personal Experience

11th June 2007

Ever since I converted it from a client-side Javascript-powered affair, my online photo gallery has been written in Perl. There have been some challenges along the way, figuring out how to use hash tables has been one, but everything has worked as expected. However, I am now wondering if it is better to write things in PHP for sake of consistency with the rest to the website. I had a go a rewriting the random photo page and, unless I have been missing something in the Perl world, things do seem more succinct with PHP. For instance, actions that formerly involved several lines of code can now be achieved in one. Reading the contents of a file into an array and stripping HTML/XML tags from a string fall into this category and seeing the number of lines of code halving is a striking observation. I am not going to completely abandon Perl, it’s a very nice language, but I do rather suspect that there is now an increased chance of I having a website whose server-side processing needs are served entirely by PHP.

Exploring AJAX

7th June 2007

When I first started it, my online photo gallery started out simply as a set of interlinked HTML pages. Over time, I discovered frames (yes, them!) and started to make use of JavaScript to make the slideshows slicker. In those days, I was working off free webspace provided by my ISP and client-side scripting was the only tool that I had for enhancing functionality. Having tired of the vagaries of client-side scripting -- the browser wars were in full swing and incompatibilities reigned supreme, I went with paid hosting in order to get access to tools like Perl and PHP for server-side processing; their flexibility compared to JavaScript was a breath of fresh air to me and I am still a fan of the server-side approach.

The journey that I have just described is one that I now know was followed by a lot of website builders around the same time. Nevertheless, I have still held onto JavaScript for some things, particularly for updating the DOM as part of making the pages more responsive to user interaction. In the last few years, a hybrid approach has been gaining currency: AJAX. This offers the ability to modify parts of a page without needing to reload the whole thing and that has generated a considerable amount of interest among web application developers.

The world of AJAX is evidently a complex one though the underlying principle can be explained in simple terms. The essential idea is that you use JavaScript to call a server-side script, PHP is as good an example as any, that returns either text or XML that can be used to update part of a web page in situ without the need to reload it as per the traditional way of working. It has opened up so many possibilities from the interface design point of view that AJAX became a hot topic that still receives much attention today. One bugbear is efficiency because I have seem an AJAX application lock up a PC with a little help from IE6. There will always remain times where server-side processing is the best route and that needs to balanced against the client-side and vice versa.

Like its forbear DHTML, AJAX is really a development approach using a number of different technologies in combination. The DHTML elements such as (X)HTML, CSS, DOM and JavaScript are very much part of the AJAX world but server-side elements such as HTTP, PHP, MySQL and XML are also very much part of the fabric of the landscape. In fact, while AJAX can use plain text as the transfer format, XML is the one implied by the AJAX acronym and XSLT is used to transform XML in HTML. However, AJAX is not limited to the aforementioned technologies; for instance, I cannot see why Perl cannot play a role in place of PHP and ASP can be used for the same things.

Even in these standards-compliant days, browser support for AJAX remains diverse, to say the least, and it is akin to having MSIE in one corner and the rest in the other. Mind you, Microsoft did introduce the tools in the first place but they used ActiveX and Mozilla created a new object type rather than continue this method of operation. Given that ActiveX is a Windows-only technology, I can see why Mozilla did what they did and it is a sensible decision. In fact, IE7 appears to have picked up the Mozilla way of doing things.

Even with the apparent convergence, there will continue to be a need for the AJAX JavaScript libraries that are currently out there. Incidentally, Adobe has included one called Spry with Dreamweaver CS3. Nevertheless, I still like to find out how things work at the basic level and feel somewhat obstructed when I cannot do this. I remember perusing Wrox’s Professional AJAX and found the constant references to the associated function library rather grating; the writing style didn’t help either.

My taking a more granular approach has got me reading SAMS Teach Yourself AJAX in 10 Minutes as a means for getting my foot in the door. As with their Teach Yourself … in 24 Hours series, the title is a little misleading since there are 22 lessons of 10 minutes in duration (the 24 Hours moniker refers to there being 24 lessons, each of one hour in length). Anything composed of 10 minute lessons, even 22 of them, is never going to be comprehensive but, as a means for getting started, I have to say that the approach seems effective on the basis of this volume. It has certainly whet my appetite for giving AJAX a go and it’ll be interesting to see how things progress from here.

WordPress 2.2

17th May 2007

WordPress 2.2 made its début yesterday and, after a spot of cautious testing, I upgraded my hillwalking blog to use it. The reason for the testing was that self-hosted WordPress blogs can now have what WordPress.com blogs have had for a while: built-in widget capability. It was this that upped my level of caution but the changes weren’t as drastic as I had feared: you need to amend your theme for widgets to be supported and not having done this causes no untoward effects. Making themes widget compatible is something that Automattic describe in a helpful article on their website. Other than this, WordPress 2..2 doesn’t cause much upheaval and, apart from pieces JavaScript snagging on occasions in Firefox, all seems well. I am still sitting on the fence as regards those widgets though…

A web development toolbox

23rd March 2007

Having been on a web-building journey from Geocities to having a website with my own domain hosted by Fasthosts, it should come as no surprise that I have encountered a number of tools and technologies over this time and that my choices and knowledge have evolved too. I’ll muse over the technologies first before going on to the tools that I use.

Technologies

XHTML

When I started building websites, HTML 4 was not long in existence and I devoured most if not all of Elizabeth Castro’s Peachpit Visual Quickstart guide to the language within a weekend. Having previously used fairly primitive WYSIWYG tools like Netscape Composer and Claris Home Page, it was an empowering experience and the first edition (it is now on its third) of Jennifer Niederst Robbins’ Web Design in a Nutshell took things much further, becoming something of a bible for a number of years.

When it first appeared, XHTML 1.0 wasn’t a major change from HTML 4, but its stricter more XML-compliant syntax was meant to point the way to the future and semantic markup was at its heart at least as much as it was for HTML 4. XHTML 2.0 is on the horizon and after the modular approach of XHTML 1.1 (which I have never used), it will be interesting to see how it develops. Nevertheless, there is a surprising development in that some people are musing over the idea of having an HTML 5. Let’s hope that the (X)HTML apple cart doesn’t get completely overturned after some years of relative stability. I still bear scars from the browser wars raging in the 1990’s and don’t want to see standards wars supplanting the relative peace that we have now. That said, I don’t mind peaceful progression.

CSS

Only seems to be coming into its own in the last few years and is truly an amazing technology in spite of the hobbles that MSIE places on our ambitions. CSS Zen Garden has been a major source of ideas; I wouldn’t have been able to customise this blog as much as I have without them. I was an early adopter of the technology and got burnt by inconsistent browser support; Netscape 4 was the proverbial bête noir back then, fulfilling the role that MSIE plays today. In those days, it was the idea of controlling text display and element backgrounds from a single place that appealed. Since then, I have progressed to using CSS to replace table-based layouts and to control element positioning. It can do more…

JavaScript

Having had a JavaScript-powered photo gallery before my current Perl-driven one, I can say that I have definitely sampled this ever-pervasive scripting language. Being a client-side language rather than a server-side one, it does place you rather at the mercy of the browser purveyors and it never ceases to amaze me that there is a buzz around AJAX because of this. In fact, the abundance of AJAX cross-browser function libraries is testimony to the need for browser-specific code. Despite my preferences for server-side scripting, I still find a use for JavaScript and its main use for me these days is to dynamically control CSS elements to do such things as control the height of a page element or whether it is shown or not. Apparently, CSS may get some dynamic capabilities in the future and reduce my dependence on JavaScript. In the meantime, Jeremy Keith’s DOM Scripting (Friends of Ed) will prove as much of an asset as it has done.

XML

These days, a lot of the raw data underlying my personal website is stored in XML. I did try to dynamically transform the display of the XML into something meaningful with CSS and XSLT when I first scaled its dizzy heights but I soon resorted to other techniques. Browser support and the complexity of what I required were the major contributors to this. The new strategy involved two different approaches. The first was to create PHP/XHTML pages from the precursor XML offline and this is how I generate the website’s directory pages. The other one is to process the XML as text to dynamically supply an XHTML page as the user visits it; this is the way that the photo gallery works.

Perl

This still powers all of my photo gallery. While thoughts of changing it all to PHP linger, there is a certain something about the Perl language that keeps it there. I suppose it is that PHP is entangled in the HTML while Perl encases the whole business and I am reasonably familiar with its syntax these days which is why it still does a lot of the data processing grunt work that I need.

PHP

PHP is everywhere these days, though it doesn’t attract quite the level of hype that used to be the case. It still appears with its sidekick MySQL in many website applications. Blogging software such as WordPress and content management systems like Drupal, Mambo and Joomla! wouldn’t exist without the pair. It appears on my website as the glue that holds my visitor directories together and is the processing engine of my WordPress blog. And if I ever get to a Drupal element to the site, by no means a foregone conclusion though I am spending a lot of time with it at the moment, PHP will continue its presence in my website scripting as it powers that too.

Applications

Macromedia HomeSite

I have a liking for hand coding, so this does most of what I need. When Macromedia (itself since taken over by Adobe, of course) took over Allaire, HomeSite sadly lost its WYSIWYG capability, but the application still soldiers on even though Dreamweaver offers a lot to code cutters these days. Nevertheless, it does have certain advantages over Dreamweaver: it is a fleeter beast to start up and colour codes Perl syntax.

Macromedia Dreamweaver

There was a time when Dreamweaver was solely a tool for visual web page development, but the advent of Dreamweaver UltraDev added server-side development capabilities to the Dreamweaver family. These days, there is only one Dreamweaver version, but UltraDev’s capabilities still live on in the latest version and I would not be surprised if they were taken further in these database-driven times.

Nowadays, Dreamweaver isn’t an application where I spend a great deal of time. In former times, when my site was made up of static HTML pages, I used Dreamweaver a lot even if its rendering capabilities were a step behind the then-current browser versions. I suppose that it didn’t fit the way in which I worked, but its template-driven workflow would have been a boon back then.

However, my move from a static site to a dynamic one, starting with my photo gallery, has meant that I haven’t used it as much since then. However, with my use of PHP/MySQL components on my site. Its server-side abilities could get the level of investigation that its PHP/MySQL capabilities allow.

Altova XMLSpy Professional

Adding MySQL databases to my web hosting costs money, not a lot but it could be spent on other (more important?) things. Hence, I use XML as the data store for my photo gallery and XML files are pre-processed into XHTML/PHP pages for my visitor directories prior to uploading onto the server.

I use XMLSpy to edit and manage the XML files that I use: its ability to view XML in grid format is a killer feature as far as I am concerned and XML validation also proves very useful; particularly with regard to ensuring that DTD’s and XML files are in step and for the correct coding of XSLT files. There are other features that I need to explore and that would also take my knowledge of the XML further to boot, not at all a bad thing.

Saxon

For processing XML into another file format such as XHTML, you need a parser and I use the free version of Saxon to do the needful, Saxonica offers commercial versions of it. There is, I believe, a parser in XMLSpy but I don’t use it because Saxon’s command line interface fits better into my workflow. This is a Perl-driven process where XML files are read and XSLT files, one per XML file, are built before both are fed to Saxon for transforming into XHTML/PHP files. It all works smoothly and updating the XML inputs is all that is required.

AceFTP

If I were looking for an FTP client now, it would be FileZilla but AceFTP has served me well over the last few years and it looks as if that will continue. It does have some extra features over FileZilla: transfers between remote sites, and scheduling, for example. I have yet to use either but they look valuable.

Hutmil

In bygone days when I had loads of static HTML files, making changes was a bit of a chore if they affected every single file. An example is changing the year on the copyright message on the page footers. Hutmil, which I found on a magazine cover-mounted disc, was a great time saver in those days. Today, I achieve this by putting this information into a single file and getting Perl or PHP to import that when building the page. The same “define once, use anywhere” approach underlies CSS as well and scripting very usefully allows you to take that into the XHTML domain.

Apache

Apache is ubiquitous these days and both the online and offline versions of my site are powered by it. It does require some configuration but it is a very powerful piece of kit. The introduction of 2.2.x meant a big change in the way that configuration files were modularised and while most things were contained in a single file for 2.0.x, the settings are broken up into different files in 2.2.x and it can take a while to find things again. Without having it on my home PC, I would not be able to use Perl, PHP or MySQL. Apart from this, I especially like its virtual site capability; very useful for offline development.

WordPress

My hosting supplier offers blogs on Blogware, but that didn’t offer the level of configuration that I would have liked. It is true that this is probably true of any host of blogs. I can’t speak for Blogger but WordPress.com does have its restrictions too. To make my hillwalking blog fit in with the appearance of my photo gallery, I went popped over to WordPress.org to download WordPress so that I could host a blog myself and have maximum control over its appearance. WordPress supports themes so I created my own and got my blog pages looking as if they are part of my website, rather than looking like something that was bolted on. Now that I think of it, what about WordPress supporting user-created themes? I support that there is the worry of insecure PHP code but what about it?

MySQL

I am between minds on whether this is a technology or a tool. SQL certainly would be a technology standard but I am not so clear on what MySQL would be. In any case, I have classed it as a tool and a very useful one at that. It is the linchpin for my WordPress blogs and, if I go for a content management system like Drupal, its role would surely grow. While I do have a lot of experience with using SAS SQL and this helps me to deal with other varieties, there is still a learning curve with MySQL that gets me heading for a good book and Kofler’s The Definitive Guide to MySQL5 (Apress) seems to perform more than adequately in this endeavour.

Paint Shop Pro

As someone who hosts an online photo gallery, it won’t come as a surprise that I have had exposure to image editors. Despite various other flirtations, Paint Shop Pro has been my tool of choice over the years, but it is now set to be usurped by a member of Adobe’s Photoshop family. Paint Shop Pro does have books devoted to it but it seems that Photoshop gets better coverage and I feel that my image processing needs to be taken up a gear, hence the potential move to Photoshop

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