Javascript like $(document).ready() for “modern HTML5” browsers

document.addEventListener('DOMContentLoaded', function () {
    /* ... */
});

The event "DOMContentLoaded" will be fired when the document has been parsed completely, that is without stylesheets* and additional images. If you need to wait for images and stylesheets, use "load" instead.

^{* only if the <script> is before the <link rel="stylesheet" ...>}