JavaScript can block DOM construction unless explicitly declared as async.

    True or false: JavaScript can block DOM construction unless explicitly declared as async.

    • False
    • True

    Correct answer is:

    • True

    Explanation: JavaScript is powerful, it can modify just about every aspect of the page, but it can also block DOM construction and delay page rendering (see also Adding interactivity with JavaScript). To keep JavaScript from delaying page rendering, AMP allows only asynchronous JavaScript.
    Read more here: https://support.google.com/partners/answer/7336293

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    Before the browser can render the page, it needs to construct the:

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