Question

通过简单检查尝试确定DOM元素

isElement = SomeThing instanceof Element

适用于主文档，但不适用于iframe中的（所有？）节点。

示例输出（Google Chrome）:(主要文档中的mdiv为DIV，iframe中的id为DIV）

OMGWTF 
ok:  mdiv instanceof Element ... true ... [object HTMLDivElement]
ok:  mdiv instanceof Object ... true ... [object HTMLDivElement]
ko:  idiv instanceof Element ... false ... [object HTMLDivElement]
KO :  idiv instanceof Object ... false ... [object HTMLDivElement]

主文档和iframe文档有不同的javascript实现???

请解释我的错误。

示例：（http://www.sbmintegral.sk/GITHUB/OMGWTF/obalka.xhtml）

代码：obalka.xhtml（主要文件）

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
   <title>Obalka</title>
  </head>
  <body>
    <div id="auto_filled_commands_container">
MAIN div id="auto_filled_commands_container"<br/>
        <iframe id="auto_filled_commands_iframe" src='dopis.xhtml' style="width:98%;height:98%;"/>
    </div>
<div>
<textarea id="OMGWTF" style="width:700px;height:200px">
mdiv = document.getElementById("auto_filled_commands_container");
ifram = document.getElementById("auto_filled_commands_iframe");
idiv = ifram.contentDocument.getElementById('auto_filled_commands');
OMGWTF = "OMGWTF \n"
+"ok:  mdiv instanceof Element ... "+(mdiv instanceof Element)+" ... "+mdiv+"\n"
+"ok:  mdiv instanceof Object ... "+(mdiv instanceof Object)+" ... "+mdiv+"\n"
+"ko:  idiv instanceof Element ... "+(idiv instanceof Element)+" ... "+idiv+"\n"
+"KO :  idiv instanceof Object ... "+(idiv instanceof Object)+" ... "+idiv+"\n"
;
document.getElementById('result_txta').value = OMGWTF;
</textarea>
<br/><input type="button" value="Eval code in upper textarea (to bypass possible developer tools error)" onclick="
    eval(document.getElementById('OMGWTF').value);
"/><b>(2.)</b><br/>
<textarea id="result_txta" style="width:700px;height:100px">
</textarea>
</div>
  </body>
</html>

代码：Dopis.xhtml（内部框架文档）

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
   <title>Dopis</title>
  </head>
  <body>
    <div id="auto_filled_commands">
IFRAME div id="auto_filled_commands"<br/>
        <div id="afc_formular">
IFRAME div id="afc_formular"<br/>
<input id="cmnd" type="text" value="input id='cmnd'" />
<br/><input type="button" value="Click to get browser userAgent" onclick="
    var preEl = this.ownerDocument.getElementById('navUserAgent');
    var cdataEl = preEl.firstChild || preEl;    /* IE don't know CDATA ?! */
    cdataEl.textContent=navigator.userAgent;
"/><b>(1.)</b>
<pre id="navUserAgent"><![CDATA[
]]></pre>
        </div>
    </div>
  </body>
</html>

结果图片（在IE，Chrome，Firefox，Opera中）image omgwtf.png http://www.sbmintegral.sk/GITHUB/OMGWTF/omgwtf.png

Answer 1

主文档和iframe文档有不同的javascript实现???

是。 iframe有自己的环境，有自己的全局变量。尝试

var iwin = ifram.contentWindow;
idiv instanceof iwin.HTMLElement; // true
idiv instanceof iwin.Object; // true

IFRAME中的instanceof HTMLElement不是Element或Object？

1 个答案: