getElementsByTagName（）在IE和FF中的行为有所不同
[英]getElementsByTagName() behaves differently in IE and FF
问题描述
I am new to JavaScript, trying to figure out a tag information value. 
我刚接触JavaScript，试图找出标签信息值。 GWT Code is as follows.. GWT代码如下。
public static native boolean isToolBarInstalled() /*-{
alert("Validating the toolbar installed.");
var metas = document.getElementsByTagName('head')[0].getElementsByTagName('meta');
var i;
alert ("Meta length: "+metas.length);
for (i = 0; i < metas.length; i++){
alert("Value: "+metas[i].value);
if (metas[i].getAttribute('name') == "toolbar"){
return true;
}
}
return false;
}-*/;
FF return true whereas IE returns false, for the same page? FF对于同一页返回true，而IE返回false？ Any clue/suggestions would be helpful. 任何线索/建议都将有所帮助。
WM. WM。
HTML is too huge to post, here is a snippet of the code.. HTML太大而无法发布，下面是代码片段。
<html>
<head>
....
<title>My App</title>
<meta name="toolbar" content="1.0">
</head>
<body>
.....
</body>
<html>
2 个解决方案
解决方案1
0 2010-10-12 20:33:38
Try this: 尝试这个：
element.attributes[value].nodeAttribute;
The getAttribute() method will return "null" in Internet Explorer when trying to get the for attribute of a label element.
Might be the same issue... 可能是同一个问题...
Well look: 好看：
In this example it is working on IE. 在此示例中，它正在IE上运行。
function isToolBarInstalled() {
alert("Validating the toolbar installed.");
var metas = document.getElementsByTagName('head')[0].getElementsByTagName('meta');
var i;
alert ("Meta length: "+metas.length);
for (i = 0; i < metas.length; i++){
alert("Value: "+metas[i].value);
var attr = metas[i].getAttribute('name');
// IE workaround
if (attr == null)
{
attr = metas[i].attributes["name"];
if (attr != null) attr = attr.nodeValue;
}
if (attr == "toolbar")
return true;
}
return false;
}
alert( "Is installed: " + isToolBarInstalled() );
解决方案2
0 已采纳 2010-10-12 21:11:23
Works for me in IE7. 在IE7中为我工作。
Check you haven't got any text content before the <meta> end-tag other than simple whitespace. 检查您是否在<meta>结束标记之前没有任何文本内容，除了简单的空白。
If you have any non-whitespace text in or before <html> or <head> , the browser will decide that you meant to open the <body> to contain the text. 如果在<html>或<head>之前或之前有任何非空白文本，浏览器将决定您要打开<body>来包含该文本。 (This is actually valid in non-XHTML HTML, as the </head> end-tag and the <body> start-tag are optional.) That means closing the <head> section, so the number of <meta> tags inside <head> will be 0. （这在非XHTML HTML中实际上是有效的，因为</head>结束标记和<body>起始标记是可选的。）这意味着关闭<head>部分，因此内部的<meta>标记数目<head>将为0。
In any case you might as well say just: 无论如何，您最好只说：
var metas= document.getElementsByTagName('meta');
as the bit about checking they're in <head> is redundant for a valid document; 因为检查它们是否在<head>中对于有效文档是多余的； that's the only place <meta> is allowed to appear. 这是允许<meta>出现的唯一位置。
alert("Value: "+metas[i].value);
There's no .value on <meta> , do you mean .content ? <meta>上没有.value ，您是说.content吗？
if (metas[i].getAttribute('name') == "toolbar"){
Use metas[i].name . 使用metas[i].name 。 There's no reason to use getAttribute / setAttribute on an HTML document and there are problems with it on IE. 没有理由在HTML文档上使用getAttribute / setAttribute ，并且在IE上存在问题。
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