I have loaded some info in a h:outputText but now I want to click a button and trigger a JS function which will take that text from the outputText.

The structure is:

<p:tabView id="tabView">
    <p:tab id="tabInvitator" title="Invitator">
         <h:form id="formInvitator">  
              <h:outputText id="inv" value="#{myController.selectedUsersFB}" />

...

But in the JS function document.getElementsById("tabView:tabInvitator:formInvitator:inv") doesn't work. It reinits the web app.

I just want to get that data and manipulate it in my JS function.
Any suggestions?

UPDATE:

I've tried with what BalusC suggested, here is my try:

   function test(){
            var arr = document.getElementsByName("tabView:tabInvitator:formInvitator:inv");
            console.log(arr);
            console.log('Arr: '+arr);
            console.log('Length: '+arr.length);

The first log returns: [ ], The second one returns: Arr: [object NodeList], The thid one: Length: 0

Why does the log return different things? And now, how can I access to that object NodeList if that's suppose a text from h:outputText?

SOLUTION IN MY ANSWER BELOW

First of all, it's a unique ID what I want to update so, the JS call would be: document.getElementById(...) (and not in plural -getElementsById-) since I will just return the data from an which contain a value, normally text.

And following my example, if I want to update firstly the outputText and after that, get that info in the JS function I can do it in a row, first updating the field (this field I put it out of any tags), and oncomplete this, call the JS function:

<p:tabView id="tabView">
  <p:tab id="tabInvitator" title="Invitator">
     <h:form id="formInvitator">
         <p:commandButton value="Invite" icon="ui-icon-comment"  update=":inv" oncomplete="sendRequestViaMultiFriendSelectorSelected();"/>
     </h:form>
  </p:tab>
</p:tabView>

<h:outputText id="inv" value="#{myController.selectedUsersFB}" />

and the Javascript function:

function sendRequestViaMultiFriendSelectorSelected() {
          var arr = document.getElementById("inv");
          console.log(arr.childNodes[0]);
          if(arr.childNodes[0]){
              console.log(arr.childNodes[0].data);
          }
          ...
}

Hope it helps someone ;)