MediaWiki:Common.js

/* Any JavaScript here will be loaded for all users on every page load. */
/* Replaces {{Username}} with the name of the user browsing the page.
   Requires copying Template:Username. */
 
function UserNameReplace() {
    if(typeof(disableUsernameReplace) != 'undefined' && disableUsernameReplace || wgUserName == null) return;
    $("span.insertusername").html(wgUserName);
 }
 addOnloadHook(UserNameReplace);
 
 importArticles({
    type: 'script',
    articles: [
        'u:dev:MediaWiki:YoutubePlayer/code.js'
    ]
});

<div class="youtubeplayer" data-id="{{{id}}}" data-width="{{{width|640}}}" data-height="{{{height|360}}}" data-autoplay="{{{autoplay|0}}}"></div>
 
/* End of the {{USERNAME}} replacement */