a function is executing an infinite loop other functions can’t be used

The problem is with how javascript is executed. Basically everything that is regarding your website is executed in one Thread (note: this isn’t completely right, but it works for us), so when you have a blocking javascript script (like a while loop) it freezes your whole website.
If you now press the stop button, it won’t execute, because your while-loop is still freezing the page.

The Solution:

Use setInterval instead like this:

    var interval_handle = undefined; //<- id of your interval. Used to stop it again
    function start() {
        stopMayInterval(); // Stop the loop, if already running
        interval_handle = setInterval( // Start the loop
          ()=>{ // Function that is looped
            console.log("start");
          }
        ,1); looped every 1 ms;
    }
    function stop() {
        stopMyInterval();
        console.log("stop")
    }

    /* Stops the Interval */
    function stopMyInterval(){
      if(interval_handle != undefined){
        clearInterval(interval_handle);
        interval_handle = undefined;
      }
    }

If you use it like this, javascript automatically queues your function every 1 ms after it has done every other thing it needs to execute for your site to work (like a button event). Documentation: https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/setInterval