function setupDOM()

in js/reveal.js [704:763]
38 lines of code
4 McCabe index (conditional complexity)

	function setupDOM() {

		// Prevent transitions while we're loading
		dom.slides.classList.add( 'no-transition' );

		if( isMobileDevice ) {
			dom.wrapper.classList.add( 'no-hover' );
		}
		else {
			dom.wrapper.classList.remove( 'no-hover' );
		}

		if( /iphone/gi.test( UA ) ) {
			dom.wrapper.classList.add( 'ua-iphone' );
		}
		else {
			dom.wrapper.classList.remove( 'ua-iphone' );
		}

		// Background element
		dom.background = createSingletonNode( dom.wrapper, 'div', 'backgrounds', null );

		// Progress bar
		dom.progress = createSingletonNode( dom.wrapper, 'div', 'progress', '<span></span>' );
		dom.progressbar = dom.progress.querySelector( 'span' );

		// Arrow controls
		dom.controls = createSingletonNode( dom.wrapper, 'aside', 'controls',
			'<button class="navigate-left" aria-label="previous slide"><div class="controls-arrow"></div></button>' +
			'<button class="navigate-right" aria-label="next slide"><div class="controls-arrow"></div></button>' +
			'<button class="navigate-up" aria-label="above slide"><div class="controls-arrow"></div></button>' +
			'<button class="navigate-down" aria-label="below slide"><div class="controls-arrow"></div></button>' );

		// Slide number
		dom.slideNumber = createSingletonNode( dom.wrapper, 'div', 'slide-number', '' );

		// Element containing notes that are visible to the audience
		dom.speakerNotes = createSingletonNode( dom.wrapper, 'div', 'speaker-notes', null );
		dom.speakerNotes.setAttribute( 'data-prevent-swipe', '' );
		dom.speakerNotes.setAttribute( 'tabindex', '0' );

		// Overlay graphic which is displayed during the paused mode
		dom.pauseOverlay = createSingletonNode( dom.wrapper, 'div', 'pause-overlay', config.controls ? '<button class="resume-button">Resume presentation</button>' : null );

		dom.wrapper.setAttribute( 'role', 'application' );

		// There can be multiple instances of controls throughout the page
		dom.controlsLeft = toArray( document.querySelectorAll( '.navigate-left' ) );
		dom.controlsRight = toArray( document.querySelectorAll( '.navigate-right' ) );
		dom.controlsUp = toArray( document.querySelectorAll( '.navigate-up' ) );
		dom.controlsDown = toArray( document.querySelectorAll( '.navigate-down' ) );
		dom.controlsPrev = toArray( document.querySelectorAll( '.navigate-prev' ) );
		dom.controlsNext = toArray( document.querySelectorAll( '.navigate-next' ) );

		// The right and down arrows in the standard reveal.js controls
		dom.controlsRightArrow = dom.controls.querySelector( '.navigate-right' );
		dom.controlsDownArrow = dom.controls.querySelector( '.navigate-down' );

		dom.statusDiv = createStatusDiv();
	}