Change style dynamically with javascript and usehref

Hello guys,

I'm using Livecycle designer and I'm trying to dynamically change the style of a TextField with javascript.

In the xml windows i've noticed the assigned style is stored in the usehref tag.

However if I try somthing like that in the "click" event of a button :

TextField.usehref = ".#som($template.#subform.designer__stylesheet.TextFieldStyle)";

This makes the TextField disappear.

Perhaps i'm doing something wrong, or maybe I have to somehow reload the layout ?

Thanks !