function test(){

var distance=null;

       first();

       second();

       third();

alert(distance);//it shows null always because it take 2 second to complete.



}

 function first(tolat, tolon, fromlat,fromlon){



// calulating road distance between two points on the map using any other distance caluculating apis. 



distance=dis;  // update the value of distance but it takes 2 second to complete.



}

 function second(){}

 function third(){}

i have this type of situation in my code, now many time function three is called before first and second complete execution and distance value is not updated.