console 命令行工具 X clear

console

window.onload = function(){
  document.querySelector('.div1').onclick = function(){
    alert('test');
  }
}

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <title>Document</title>
</head>
<body>
  <div class="div1"></div>
</body>
</html>

.div1{
  width: 200px;
  height: 200px;
  background-color: red;
  margin:200px auto;
}