Bootstrap/Tabs: remember active tabs

[yii-bot]

This issue has originally been reported by @RomeroMsk at yiisoft/yii2#4890.
Moved here by @cebe.

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Just a feature request: config option to "remember" active tab in Tabs widget (to activate last opened tab after reloading the page).
It is not so hard to implement with application JS, but can be a feature of widget. We need to register just two event handlers:

1. Set location.hash on tab click:

$(document).on('click.bs.tab.data-api', '[data-toggle="tab"], [data-toggle="pill"]', function (e) {
    location.hash = e.target.hash;
});

We need this because of https://github.com/twbs/bootstrap/blob/master/js/tab.js#L126
2. On document ready activate the tab:

$(document).ready(function() {
    if (location.hash.length) {
        $('[data-toggle="tab"], [data-toggle="pill"]').filter('[href="' + location.hash + '"]').tab('show');
    }
}

[melledijkstra]

@cebe Is this already implemented? Or is this still in development?

[schmunk42]

We implemented this with local storage a while ago. https://github.com/dmstr/yii2-bootstrap But the code should be cleaned.

[melledijkstra]

@schmunk42 Thanks! Would be nice if they implement it into yii2