code: function findSupported(apiList, document) {
  
  	let standardApi = apiList[0];
  	let supportedApi = null;
  
  	for (let i = 0, len = apiList.length; i < len; i++) {
  
  		let api = apiList[ i ];
  
  		if (api[1] in document) {
  			supportedApi = api;
  			break;
  		}
  	}
  
  	if (Array.isArray(supportedApi)) {
  
  		return supportedApi.reduce((result, funcName, i) => {
  			result[ standardApi[ i ] ] = funcName;
  			return result;
  		}, {});
  
  	} else {
  
  		return null;
  	}
  }
docs: Finds a supported fullscreen API.
  
  @param   {Array}    apiList      The list of possible fullscreen APIs.
  @param   {Document} document     The source of the fullscreen interface.
  @returns {Object}