Day: October 14, 2009

Categories
Javascript SEAM XHTML

The XHTML and document.write / innerHTML story

If you use XHTML as HTML-Standard, which is recommended, to build your sites and you use JavaScript, you could have problems with document.write. Especially third-party JavaScript extensions like GoogleMaps or CKEditor use document.write to easily inject own JavaScript code.

But this is denied by specification for XHTML-Documents delivered with content-type application/xhtml+xml instead of text/html. You will receive the DOM Exception #7 by calling document.write or while using innerHTML (Example in Safari: “Error: NO_MODIFICATION_ALLOWED_ERR: DOM Exception 7”; in Firefox: uncaught exception: [Exception… “Component returned failure code: 0x80004003 (NS_ERROR_INVALID_POINTER) [nsIDOMNSHTMLElement.innerHTML]”  nsresult: “0x80004003 (NS_ERROR_INVALID_POINTER)”  location: … ]). The solution is to deliver the Website with content-type “text/html” instead of “application/xhtml+xml”.
Errormessage Safari
In SEAM using Facelets (with JSF) as View, you can set the content-type in the f:view-Tag. This would look like:

?View Code XML
1
2
3
4
5

...
<f :view contentType="text/html">
....
</f>
...
Categories
SEAM Tomcat

Defining a ServletFilter – the SEAM way

SEAM doesn’t only extends JSF and Facelets, but also gives you a possibility to define other resources or components via annotations. To define a simple Servlet Filter you only need to annotate a class with the @Filter-annotation. There is no need to extend the web.xml or other.

One simple Filter would be:

?View Code JAVA
1
2
3
4
5
6
7
8
9
10

@Scope(ScopeType.APPLICATION)
@Name("myFilter")
@Install(precedence = Install.FRAMEWORK)
@BypassInterceptors
@Filter(within = { "org.jboss.seam.web.rewriteFilter" })
public class MyFilter extends AbstractFilter {
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        chain.doFilter(request, response);
    }
}

With the parameters within or around of the @Filter annotation, you can define when you filter will be called.

Categories
JQuery

test if html element is visible with JQuery

If you use JQuery you can use the effects for dynamically hide and show html-elements, like boxes and so. But how to test if such a element is currently visible or not? JQuery offers here some selectors, named :hidden and :visible, which can be used. If you combine it with the “is” method, you can easily check the state.

?View Code JAVASCRIPT
1
2
3

alert($("p").is(":visible"));
$("p").hide();
alert($("p").is(":visible"));

This code would output “true”, “false” for a normal p-tag.