DOMContentLoadedの発火とスタイルシートの読み込みは間接的に関係あるらしい MDNのDOMContentLoadedのページみてたら The DOMContentLoaded event is fired when the document has been completely loaded and parsed, without waiting for stylesheets, images, and subframes to finish loading (the load event can be used to detect a fully-loaded page). Note: Stylesheet loads block script execution, so if you have a <script> after a <link rel="styleshe