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GWT Mini Pattern: Make Your Links Friendly To All Users

Sometimes GWT widgets are used to provide functionality, like a form submission, that is easily replicable in traditional HTML. Other times, it’s not so easy to create a user interface that degrades well. Luckily, the self contained nature of widgets means that crucial functionality is typically still available to users with javascript disabled. However, you can take steps to make your site more friendly to users with javascript disabled (for whatever reason).

For the first case, where there is a viable HTML analog, the solution is to have your widget home span look something like this:

<span id="requestinfocuspan"><span class="clickable-link" id="requestinfocuspanplaceholder"><a xhref="/" mce_href="/" >Request More Info</a></span></span>

Now, if the user has javascript disabled, and they click on the href, they are sent to the appropriate HTML form. However, if the user has javascript enabled, the widget looks for a span to enable and if it sees the “requestinfocuspan” span, calls code like this:

public static Label buildClickableLink(String span, ClickListener listener) {
Element placeHolderLink = DOM.getElementById(span+"placeholder");
String contentsOfPlaceHolder = "Content unavailable";
Element placeHolderSpan = DOM.getElementById(span);
if (placeHolderSpan != null && placeHolderLink != null) {
contentsOfPlaceHolder = DOM.getInnerText(placeHolderLink);
DOM.removeChild(placeHolderSpan, placeHolderLink);
Label clickme = new Label(contentsOfPlaceHolder);

return clickme;

This code takes the contents of “requestinfocuspan”, grabs the text of the span inside it, and replaces the whole of the contents with a label. That label has the same text and a click listener attached, so there’s no bouncing of text. If a designer wants to change the text of this link, they can do so by modifying the JSP without touching (or redeploying) GWT components.The second case mentioned above, where there is no easy way to build an HTML interface for GWT functionality, can be handled by placing a link to a page explaining to the user that javascript is required, and possibly how to turn it on. An easy way to show that link for non javascript users is to use the noscript tag

<script type="text/javascript">document.write("<a xhref='/psaf&city=Boulder'>Advanced Search Form</a>");</script>
<noscript><a xhref='/'>Advanced Search Form</a></noscript>

This is a viable option here because there is no need to run the ‘buildClickableLink’ method. We don’t really need a click listener, because we have a plain href to a page that the GWT component will run on.

The other option is to use the existing link method discussed above and use the buildClickableLink method:

<span id="searchspan"><span class="clickable-link" id="searchspanplaceholder"><a
xhref="/" mce_href="/" >Advanced Search</a></span></span>

While accessibility to non javascript users is not built into GWT (although it might be on the way), you can take steps to make your widgets more friendly to these users. This is especially true if you’re merely ‘ajaxifying’ existing functionality. In addition, users with javascript enabled get a better user experience if you use some of the above methods because the text on the page doesn’t ‘jump around’ when GWT code is executed after the page is loaded.

PS Sorry for the ‘xhref’s in my links above–I’m not quite sure how to turn off the escaping that WordPress or TinyMCE does.  Please replace ‘xhref’ with ‘href’ wherever you see it.