Adding a namespace to HTML tag

Adding a namespace to HTML tag

In Outsystems, how do you add a namespace to the HTML tag?

Is there an extension/ components to use? If so which extension/component do you use to add a namespace to the HTML Tag?

  <html xmlns="" xmlns:fb="">  
Hi Robert,

This sometimes comes up, and the suggestion is to use the HTTPRequestHandle extension, namely an action which is the AddPostProcessingFilter.

See if this post helps. There's some other references of that action for similar uses throughout the forums.

Let us know how it goes.


Paulo Tavares

It does not work.

Found that "AddPostProcessingFilter" would replace any html elements under the html tag, but it would not replace the html tag itself.

Unable to replace this line
<html xmlns="" >

<html xmlns="" xmlns:fb="" >  
Hi Robert,

Indeed it doesn't.
You might need to explore ASP.Net library for a way to do that and create an extension to encapsulate that functionality, or contact our technical support team so they can help you with that.

Tiago Simões
Hi Robert,

Following this Microsoft post ( you can add the "xmlns" in any HTML tag.

Can you try to add this namespace in for example the Header or Body tag using the  HTTPRequestHandle extension?

With best regards,
Renato Gonçalves
Renato, Yes, you are right you can add xmlns to any HTML tag however the problem is, you are unable to do add xmlns in outsystems, because you can not edit the html tag manually as there is no access to the html source code, in addition there is no functions/actions to modify the html tag either.

Hi Robert,

As a workaround for this misbehavior you can add a Div Elemnet with this reference and add your content within the Div.

You can do this using an Expression (in your Web Screen) with the Escape content set to "no" (e.g "<div xmlns:fb="" >")

Best regards,
Renato Gonçalves
I had the same problem last year and ended up creating an extension which tweaks the html tag itself and inserts the facebook xmlns.   I've attached a simple version of the extension.  Include this in your project, and drag the FB_NamespaceInit action to your preparation step of your screen and it will include the facebook namespace.

I hope this helps you out.