From the youtube player http://code.google.com/apis/ajax/playground/?exp=youtube#chromeless_player I get a time value in seconds, like '243.577'. Let it be a simple string.
How do I convert it to the value like: '04:35'? Like 4 minutes and 35 seconds (hope I made right calculations) for this example.
If the value is just 5 seconds, then it should give something like '00:05'. If negative, then '00:00'.
var raw = "-54";
var time = parseInt(raw,10);
time = time < 0 ? 0 : time;
var minutes = Math.floor(time / 60);
var seconds = time % 60;
minutes = minutes < 10 ? "0"+minutes : minutes;
seconds = seconds < 10 ? "0"+seconds : seconds;
alert(minutes+":"+seconds);
Working demo: http://jsfiddle.net/8zPRF/
UPDATE
Some added lines for negative numbers and string format: http://jsfiddle.net/8zPRF/3/