SOURCE

function createOrder() {
  var coffee = document.forms[0].coffee;
  var txt = '';
  for (var i = 0; i < coffee.length; i++) {
    if (coffee[i].checked) {
      txt += coffee[i].value + ' ';
    }
  }
  document.getElementById('order').value = "您选择的咖啡里面还添加了：" + txt;
}
function UpperCase(){
  document.getElementById('input').value=document.getElementById('input').value.toUpperCase();
 
}

<form action="">
  <p>
    喝咖啡通常喜欢加什么
  </p>
  <input type="checkbox" name="coffee" value="奶油" />
  加奶油
  <br>
  <input type="checkbox" name="coffee" value="方糖" />
  加方糖
  <br>
  <br/>
  <input type="text" id="order" size="50" />
  <input type="button" onclick="createOrder()" value="选择好了" />
</form>
<div>
  <input type="text" id="input" onblur="UpperCase()" />
  <button onclick="UpperCase()">UpperCase</button>
</div>