jQuery multithreading : How to make 2 functions run parallely?

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Javascript

jQuery

HTML5

PhoneGap

I am developing Phonegap build game application, where we have 2 parts in single screen which corresponds 2 functions. 1st function will display random image and text in first part. 2nd function will take care of new level in second part. Now the problem is , the UI is completely disturbed since javascript by default single threaded and executes serially! So, How can I overcome this? I tried with async.js plugin, but no use. I don't want to use setTimeOut or setTimeInterval as I read in some posts.

Here is my code snippet:

function checksquence(){
  //if correct
  if(turn == array.length) {
    level++;

     displayMarquee(); // 1st function
     newlevel(); //2nd function
   }
}

Any help greatly appreciated.