Prototype - empty() 方法

此方法测试元素是否为空(即，仅包含空格)。

语法

element.empty;

返回值

如果发现元素为空，则返回 true，否则返回 false。

示例

<html>
   <head>
      <title>Prototype examples</title>
      <script type = "text/javascript" src = "/javascript/prototype.js"></script>
      
      <script>
         function showResult() {
            if($('wallet').empty() ) {
               alert( "Wallet is empty " );
            }
            if($('cart').empty() ) {
               alert( "Cart is full" );
            }
         }
      </script>
   </head>

   <body>
      <p>单击按钮查看结果。</p>
      <div id = "wallet">     </div>
      <div id = "cart">full!</div>
      <br />
      <input type = "button" value = "showResult" onclick = "showResult();"/>
   </body>
</html>

In this example −

$('wallet').empty();
// -> true
$('cart').empty();
// -> false

输出

prototype_element_object.html