Pentadactyl ex file defining commands to go back/forward in a duplicated tab (like middle-clicking the navigation buttons)

backt-forwardt.penta

" Pentadactyl ex file: add to .pentadactylrc or source with :source command
" Defines commands to go back/forward in a duplicated tab (equivalent to middle-clicking the navigation buttons)

" Example keybindings: gh and gl (replacing the builtin gh binding):
unmap gh
map -g user -ex gh :backt
map -g user -ex gl :forwardt

command! backt
    \ -description "Duplicate tab and go back in the browser history"
    \ -js <<EOF
    var currT = gBrowser.selectedTab;
    var dupT = gBrowser.duplicateTab(currT);
    var dupTB = gBrowser.getBrowserForTab(dupT);
    var backtListener = function () { 
        gBrowser.goBack(); 
        dupTB.removeEventListener("DOMContentLoaded", backtListener);
    };          
    dupTB.addEventListener("DOMContentLoaded", backtListener);
    gBrowser.selectedTab = dupT;
EOF

command! forwardt 
    \ -description "Duplicate tab and go forward in the browser history"
    \ -js <<EOF
    var currT = gBrowser.selectedTab;
    var dupT = gBrowser.duplicateTab(currT);
    var dupTB = gBrowser.getBrowserForTab(dupT);
    var forwardtListener = function () {
        gBrowser.goForward();
        dupTB.removeEventListener("DOMContentLoaded", forwardtListener);
    };
    dupTB.addEventListener("DOMContentLoaded", forwardtListener);
    gBrowser.selectedTab = dupT;
EOF