add new todo

Author: chrisweb

README.md

@@ -464,6 +464,7 @@ things I intend to add some day or if you want to help but are not sure what to
 
 if you are interested in helping out 😊 by working on one of the following TODOs, please start by reading the ["contributing"](#contributing-prs-welcome) chapter above
 
+* add an option to the sound to allow setting a custom media element for audio element mode!? similar to arraybuffer and soundbuffer for ajax mode
 * for audio mode, add option for songs "crossOrigin" to be set to "use-credentials" [HTML attribute: crossorigin](https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/crossorigin) instead of "anonymous", "anonymous" could be kept as default value, also do the same for XHR calls (ajax mode) [XMLHttpRequest: withCredentials property](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/withCredentials)
 * add a song feature to fade out (current song) / fade in (next song) maybe two new options fadeInDuration and fadeOutDuration would be enough, if the values are set we do a fade
 * add onDurationChange / onLoopChange callbacks to song(s)!?