function update_chord(d){var a=document.getElementById("instrument_id").selectedIndex;if(a<0){return}var c=document.getElementById("instrument_id").options[a].value;a=document.getElementById("note_id").selectedIndex;if(a<0){return}var b=document.getElementById("note_id").options[a].value;document.getElementById("chord").innerHTML="<img src='playalong_chord.php?instrument_id="+c+"&note_id="+b+"'/>"}function init(){update_chord(null);YAHOO.util.Event.addListener(document.getElementById("instrument_id"),"change",update_chord);YAHOO.util.Event.addListener(document.getElementById("note_id"),"change",update_chord)}YAHOO.util.Event.onDOMReady(init);