Page Assembler Strips Empty Elements -- This is Good!

With the new release of PeopleTools and Enterprise Portal, I find myself modifying my old branding themes to incorporate new features. While testing a header, I noticed that it appeared correctly on homepages, but not on transaction pages. Upon further inspection, I noticed that certain HTML elements I included in my HTML definition appeared on homepages, but not on transaction pages. Specifically, if an HTML element had a bind variable as its only content and that bind variable was only relevant on a homepage, then the page assembler would strip my hard-coded empty element from the transaction page. This caused me a bit of concern because I was actually using those elements to provide layout and styling. Consider the "Personalize Content | Layout" links that usually appear underneath the tabs in a standard Enterprise Portal implementation. Those links only appear on homepages, not on transaction pages. The PeopleSoft branding/assembly code uses designated bind variables to insert those links into a header HTML definition. If you wrap a block element, such as an HTML div around that bind variable, then your div will appear on a homepage, but not on a transaction page.

When I saw this behavior the other day I was quite surprised... and then I remembered I had seen it before. Several years ago while working with page level HTML Areas and Ajax, I noticed the same behavior. It is quite common to insert empty, hidden div elements and other structural elements into HTML to act as containers for dynamic content. The only problem with this approach is that the page assembler seems to eliminate these empty elements. Here is the workaround I contrived for this issue: Add an HTML comment inside an empty HTML element as follows:

<div id="jjm_dynamicContent" style="height: 10px; background-color: blue;">
  <!-- This comment will force the page assembler to render this element -->
</div>

The page assembler will see content (the comment) inside the element and will allow it to pass through to the browser. Since the content is a comment, the browser will ignore the content and treat the element as if it were empty, giving us our much desired empty element.

Now that we have a solution for creating empty elements, let's consider how to turn this seemingly annoying behavior into a positive feature. The PeopleTools branding makes extensive use of HTML definitions. These HTML definitions contain bind variables that may or may not have values, depending on the execution context. I've already given the example of the Personalize links on a homepage. Wrapping items like these in HTML containers, such as div elements, provides us with conditionals that otherwise might not exist. For example, by wrapping the Personalize bind variable in a named div, you create a div that will exist on homepages, but not on transaction pages. Using JavaScript, you can test for the existence of this named element and execute code accordingly. Likewise, you can use CSS to attach layout and design instructions to these elements that the browser will only apply if the element exists (conditions are met).

There was a time when I thought this was a bug that should be fixed. But, now that I am enlightened to the possibilities of conditionals, I see the benefits of this feature and would be very sorry to see this behavior change.