Thanks for your response.
A new tab opens using getItems values generated from input data by users. Each time the users changes the input & getItem values change, a new tab opens.
The problem is, if they refresh any of the tabs (in error) the data is overwritten with the latest getItem values resulting in incorrect data for that tab.
At the end of their online session they close all of the tabs.
Is there a way of running the getItems function only once for each new tab & saving the data as constant values?