jquery not（）has（）

Question

我正在研究一個page，我在其中動態創建一個Facebook Like按鈕，當用戶單擊一個圖片圖標時。 （由於頁面上有很多項目，如果我沒有這樣做，頁面加載就會嚴重抓取。）。

如果我螢火蟲中運行以下命令：

var $clickTrackerGroup= $("#click-tracker-91"); 
console.log ($(".user-message-block", $clickTrackerGroup).html()); 
if ($(".user-message-block:has(div.hbo-message_likeBtn)", $clickTrackerGroup)) { 
     console.log("this group DOES NOT have an iframe"); 
} else { 
     console.log("this group DOES have an iframe"); 
    } 

我得到這個：

<div class="image-container"> 
    <img src="http://graph.facebook.com/1422524707/picture" id="person-222-clicked" alt="AMANDA H" title="AMANDA H" width="50px" height="50px"></div> 
    <div class="user-message"> 
     <span class="message-text"> 
      "ipsum lorem....."</span> 
      <div class="message-create-time"> 
       <span class="create-time">1/28/2011 7:33:17 AM</span> 
       <span class="user-name"> - Amanda H.</span> 
      </div> 
    </div> 
    <div class="hbo-message_likeBtn"> 
     <iframe src="http://www.facebook.com/plugins/like.php?href=http%3A%2F%2Fwww.honeybunchesofoats.com%2FBunchesOfLove.aspx%2FMessage%2F250&amp;layout=standard&amp;show_faces=false&amp;width=250&amp;action=like&amp;colorscheme=light&amp;height=35" 
      style="border: medium none ; overflow: hidden; width: 250px; height: 35px;" allowtransparency="true" 
      frameborder="0" scrolling="no"></iframe> 
     </div> 

this group does not have an iframe 

我也試過：

if ($(".user-message-block:has(iframe)", $clickTrackerGroup)) { 
    console.log("this group DOES have an iframe"); 
} else { 
    console.log("this group DOES NOT have an iframe"); 
    } 

你可以清楚地看到，HTML的此塊事實上，它有一個iframe。

如何成功測試此元素的存在？

感謝， 斯科特

Answer 1

如何：

if ($(".user-message-block iframe", $clickTrackerGroup).length === 0) { 
    // no iframe selected => iframe does not exist 
    console.log("this group does not have an iframe"); 
} 

參考：.length

Answer 2

嘗試

if ($(".user-message-block:has('iframe')", $clickTrackerGroup)) { 
     console.log("this group does not have an iframe"); 
}