var sessionLength=25;
var breakLength=5;
var sound = document.getElementById("audio");
var timer=10;
var count=breakLength*60;

$(document).ready(function(){
    function checkCount(){
      count=count-1;
      if (count <= 0){
        $("#counterShow").html("00:00");
        clearInterval(counter);
        console.log("hey");

        console.log("Check if timer returned and play sound");
        sound.play()
      }

      $("#counterShow").html(Math.floor(count/60)+":"+count%60);
    }

     $(".img").click(function(){
        counter=setInterval(checkCount, 1000); //setInterval is an async function. It returns immediately, and your program continues running from the next line. The function checkCount is called everyone 1000ms.
        count=sessionLength*60;
        timer=10;
    });
});