Question

I have 2 scripts

script1 = function() {
    // takes very long time
}

script2 = function() {
    // takes less time
}

I want to ensure that script2 should run after script1 is complete.

Answer 1

put your script2 to script1. Or for more general solution make script1 function to receive callback function(script2) and call it.

This is the way of many many jquery async functions

script1 = function(callback){
      //takes very long time
      callback();
}


script2 = function(){
      //takes less time
}
...
//call like this
script1(script2);