Udtab onclick edit style

I have a tab content hidden i would like to display by either clicking on a tab which would trigger the tabs content to display or by clicking a button which would display the hidden tab and its content

Is it possible to use onclick on a tab?

Im close to getting the button option to work, i have the tab hidden by setting its display style to none via theme but cant figure out how to use the buttons onclick to set the tabs display via theme to block to display the hidden tab

Any help much appreciated