Material Component Web - MDCTab - How to set active tab in javascript

Question

I have got two tabs (TAB1 and TAB2). Active tab is TAB1 (mdc-tab--active). I want to set active tab to TAB2 using javascript.

Thanks.

My code:

   <div class='mdc-tab-bar' role='tablist' data-mdc-auto-init='MDCTabBar'>
        <div class='mdc-tab-scroller'>
            <div class='mdc-tab-scroller__scroll-area mdc-tab-scroller__scroll-area--scroll'>
                <div class='mdc-tab-scroller__scroll-content'>
                    <button class='mdc-tab mdc-tab--stacked mdc-tab--active' role='tab' aria-selected='false' tabindex='-1'>
                        <span class='mdc-tab__content'>
                            <span class='mdc-tab__icon mdc-tab__icon-fa fa fa-comments fa-2x' aria-hidden='true'></span>
                            <span class='mdc-tab__text-label'>TAB1</span></span>
                        <span class='mdc-tab-indicator mdc-tab-indicator--active'>
                            <span class='mdc-tab-indicator__content mdc-tab-indicator__content--underline'></span>                                  
                        </span>
                        <span class='mdc-tab__ripple'></span>                               
                    </button>

                    <button class='mdc-tab mdc-tab--stacked b_mensajes_tabs_contactos' role='tab' aria-selected='true' tabindex='1'>
                        <span class='mdc-tab__content'>
                            <span class='mdc-tab__icon mdc-tab__icon-fa fa fa-user-circle fa-2x' aria-hidden='true'></span>
                            <span class='mdc-tab__text-label'>TAB2</span></span>
                        <span class='mdc-tab-indicator'>
                            <span class='mdc-tab-indicator__content mdc-tab-indicator__content--underline'></span>                                  
                        </span>
                        <span class='mdc-tab__ripple'></span>                               
                    </button>
                </div>
            </div>
        </div>
    </div>
.....
<script>
window.mdc.autoInit ();
</script>

I'm using de latest version of material-components-web

https://unpkg.com/material-components-web@latest/dist/material-components-web.css

https://unpkg.com/material-components-web@latest/dist/material-components-web.js

Answer 1

You can use the activateTab function to activate a tab. For this you need the top bar instance. The documentation on mdc-auto-init states that you can get the component instance via the element:

Once mdc.autoInit() is called, you can access the component instance via an MDCTextField property on that element.

In your case the result is as follows:

var element = document.querySelector('[data-mdc-auto-init="MDCTabBar"]');
elem.MDCTabBar.activateTab(1);