Setting span html element text in C++

Hi,

I am writing firefox extension using C++.
I want to set text of the span html element.

In Javascript, I used 'textcontent' javascript property to set span
element text.

How can I do it in C++?

I found nsIDOMHTMLElement interface & its child interfaces.

They seem useful.

I am not getting the way in which I will use nsIDOMHTMLElement
interface & its child interfaces to set span element text.

Please suggest me the way!

Thanks,
Vaibhav.