Hiding a tab based on whether a field Contains Data or not

Hi everyone

I'm trying to show or hide a tab based on whether or not a field contains data.

The basic principle is if a field called Type contains data then tab_16 should show. If the field called Type does not contain data then tab_16 should not show.

I know that I have to do this in Javascript, and I believe that I might have got part of the way. However, I know that the second part of the code is wrong, but my experience of Javascript is very minimal! Could anyone help me with this please?

Also, how do I ensure that tab_16 shows if Type changes from not containing data to containing data?

function hideOrShowSubgrids() {

var taskTab = Xrm.Page.ui.tabs.get('tab_16');

//Time out function to wait untill the component loads.
if (taskTab == null || taskTab == "undefined") {
setTimeout(function () { hideOrShowSubgrids(); }, 1000);
return;
}

//Set the tab as visible if the Field "Type" contains data.
if (fieldname == "Type") {
Xrm.Page.ui.tabs.get('tab_11').setVisible(true);
}
}

Many thanks
Jon