No you cannot do that. Because the outputText text is rendered BEFORE the page is sent to the client, and therefore before the JavaScript runs.
What you can do is have JavaScript alter the text of that control AFTER the page is rendered as a standard DOM modification process. You can even use jQuery to do the job, since jQuery is automatically included as part of RichFaces.
Don't forget, however, that when using jQuery in
JSF that the "$()" expression form should be avoided (use the "jQuery()" form) and that the ID of the outputText control that the will be the element's low-level ID, and not the simple "id=" value in the JSF control.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.