JavaScript_basic/event5.html at main · deepeshahirwar/JavaScript_basic · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title> Asynchronous js</title>
</head>
<body >
   <h2> Start should changne the background color every second </h2>
   <button id="start">Start</button>
   <button id="stop">Stop</button>
</body>
 <script>
 //setInterval  ,clearInterval
 // for creating random colors
 const randomColor = function(){
  const hex ="0123456789ABCDEF";
  let color ="#";
  for(let i=0; i<6; i++){
    color += hex[Math.floor(Math.random()*16)];
  }
  return color;
 }
 let intervalId;
const startChangeColor = function(){
    if(!intervalId){
        intervalId=  setInterval(changeBgColor, 1000);
    }

    function changeBgColor(){
        document.body.style.backgroundColor =randomColor();
    }

};
const stopChangeColor = function(){
   clearInterval(intervalId);
   intervalId =null;
   console.log("bc stopped")
};

 document.querySelector('#start').
addEventListener('click', startChangeColor);

document.querySelector('#stop').
addEventListener('click', stopChangeColor);


</script>
</html>