Tampermonkey Cheatsheet

tampermonkey_cheatsheet.md

Access Tab Data

// Get our tab object and save some data into it
GM_getTab(function(tab_self) {
    tab_self.created = Date.now();
    tab_self.location_href = window.location.href.toString();
    GM_saveTab(tab_self);
});

// Get our tab object and then compare it to all the other tab objects
// TODO: namespacing? or other tabs that aren't executed in our script.
// TODO: Better way to determine self vs. other tab?
// TODO: Better way for tab IDs?
GM_getTab(function(self_tab) {
    GM_getTabs(function(tabs) {
        for(const i in tabs) {
            let tab = tabs[i];
            if (tab.created === self_tab.created && tab.location_href === self_tab.location_href) {
                console.log('Tab ' + i + ' is us');
                continue;
            }
            if (tab.location_href === self_tab.location_href) {
                console.log('Tab ' + i + ' is on the same URL as us, they were created at ' + tab.created);
            }
        }
    });
});

Trigger Events Across Tabs

// If you want to trigger something from the tampermonkey menu, add a command to it
// Have it write a new value to trigger_event_here, current time is just convenient
GM_registerMenuCommand("Trigger Event", function(e) {
    GM_setValue('trigger_event_here', Date.now());
});

// Add a listener that watches for any change to the shared value trigger_event_here
GM_addValueChangeListener('trigger_event_here', function(key, oldValue, newValue, remote) {
    console.log('Event triggered by ' + (remote ? 'another tab ' + 'us'));
    // Do stuff
});

Communicate Across Tabs

// TODO: Same event idea, but can pass data as the event object or something