Unity3D Game Time

Hi,can someone please help me to make game time in GUI,in this format: ‘‘0:00’’ .And it will stop when i die or finish level.Please help.

Updated:

var sec : float = 0;
var intsec : int;
var minutes = 0;
var seconds;
var time;

function Update() {

sec = sec + Time.deltaTime;

}


function OnGUI() {

intsec = sec;

 if(intsec < 10)
 {
  seconds = "0"+intsec;
 }
 else
 {
  seconds = intsec;
 }

 if(intsec >= 60)
 {
  minutes++;
  sec=0;
 }

 time = minutes + ":" + seconds;

 GUI.Label (Rect (10, 10, 100, 20), time);

}