为什么jquery返回0为offsetHeight当firebug说它是34？ [英] Why would jquery return 0 for an offsetHeight when firebug says it's 34?
问题描述
所以，我以为我可以通过这样做jquery ...
$（＃parentDiv）。attr（'offsetHeight'）;
或直接js ...
的document.getElementById（ parentDiv）的offsetHeight。
但是返回的所有值都是0.与偏移高度是在这种情况下只读属性？如何获得这个高度？我的意思是firebug正在以某种方式弄清楚它，似乎我应该能够。
编辑：
以下是现在的div的样例...
<！DOCTYPE HTML PUBLIC - // W3C // DTD HTML Strict // EN>< META http-equiv =Content-Type content =text / html; charset = utf-8>
< HTML style =OVERFLOW：hidden; HEIGHT：100％xmlns =http://www.w3.org/1999/xhtml>< BODY>< FORM id =aspnetFormname =aspnetFormaction =blah.aspxmethod =post>< DIV id =container>
< DIV id =ctl00_BodyContentPlaceHolder_Navigationstyle =Z-INDEX：1; LEFT：1597px; POSITION：absolute; TOP：67px>
< DIV class =TransparentBgid =TransparentDivstyle =MARGIN-TOP：10px; MARGIN-RIGHT：10px; HEIGHT：94px; TEXT-ALIGN：center>
< / DIV>
< DIV class =Foregroundid =ForegroundIdstyle =MARGIN-TOP：10px; MARGIN-RIGHT：10px; TEXT-ALIGN：center>
< DIV id =ctl00_BodyContentPlaceHolder_Navigation1style =WIDTH：52px; COLOR：black; HEIGHT：52px; BACKGROUND-COLOR：transparent; -moz-user-focus：normal>
< IMG style =FILTER：progid：DXImageTransform.Microsoft.AlphaImageLoader（sizingMethod = scale src ='.. / images / image.gif'）; CURSOR：指针height =52hspace =0 src =...width =52/>
< / DIV>
< DIV id =ctl00_BodyContentPlaceHolder_UserControlname =ctl00_BodyContentPlaceHolder_UserControl>
< IMG style =DISPLAY：block; VERTICAL-ALIGN：bottom; CURSOR：pointerheight =17src =...width =16/>
< IMG style =VERTICAL-ALIGN：top; CURSOR：pointerheight =17src =...width =16/>
< / DIV>
< / DIV>
< / DIV>
< / DIV>< / FORM>< / BODY>< / HTML>
此代码由单独库中的控件生成。所以这里是我的.aspx页面中的实际代码。
< blah：blahControl ID =controlrunat =服务器/>好的，它稍作修改，但是比以前更多的HTML。之前被称为parentDiv的div在那里被称为ctl00_BodyContentPlaceHolder_UserControl。该代码包括有问题的div，它是兄弟，父母，祖父母和孩子。这几乎是firebug的直接副本。
更新：
我应该提到这是在IE 7中完成的。在Firefox中工作一次，但现在返回0。这是否提供了可能的解决方法或任何新的见解？
...你们都必须认为我是坚果。
更新：
某些样式...
.TransparentBg
{
background-color：white;
过滤器：alpha（opacity = 50）;
-moz-opacity：0.5;
-khtml-opacity：0.5;
不透明度：0.5;
}
.Foreground
{
position：absolute;
顶部：0px;
}
解决方案你确定它不是 Heisenbug ？如果您以编程方式设置高度，然后稍后尝试阅读，那么DOM将不会更新。
So I have a div whose content is generated at runtime it initially has no height associated with it. When it's generated according to firebug and from what I can alert with js the div still has a height of 0. However, looking at the read-only properties with firebug I can see that it has an offset height of 34. It's this value that I need. Hopefully it's obvious but in case it isn't, this number is variable, it's not always 38.
So, I thought that I could just get that by doing this via jquery...
$("#parentDiv").attr('offsetHeight');
or this with straight js...
document.getElementById("parentDiv").offsetHeight;
But all that is returned is 0. Does it have anything to do with the fact that offset height is a read-only property in this instance? How can I get this height? I mean firebug is figuring it out somehow so it seems like I should be able to.
Edit:
Here's a sample of what the div looks like right now...
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML Strict//EN"><META http-equiv="Content-Type" content="text/html; charset=utf-8">
<HTML style="OVERFLOW: hidden; HEIGHT: 100%" xmlns="http://www.w3.org/1999/xhtml"><BODY><FORM id="aspnetForm" name="aspnetForm" action="blah.aspx" method="post"><DIV id="container">
<DIV id="ctl00_BodyContentPlaceHolder_Navigation" style="Z-INDEX: 1; LEFT: 1597px; POSITION: absolute; TOP: 67px">
<DIV class="TransparentBg" id="TransparentDiv" style="MARGIN-TOP: 10px; MARGIN-RIGHT: 10px; HEIGHT: 94px; TEXT-ALIGN: center">
</DIV>
<DIV class="Foreground" id="ForegroundId" style="MARGIN-TOP: 10px; MARGIN-RIGHT: 10px; TEXT-ALIGN: center">
<DIV id="ctl00_BodyContentPlaceHolder_Navigation1" style="WIDTH: 52px; COLOR: black; HEIGHT: 52px; BACKGROUND-COLOR: transparent; -moz-user-focus: normal">
<IMG style="FILTER: progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod = scale src='../images/image.gif'); CURSOR: pointer" height="52" hspace="0" src="..." width="52" />
</DIV>
<DIV id="ctl00_BodyContentPlaceHolder_UserControl" name="ctl00_BodyContentPlaceHolder_UserControl">
<IMG style="DISPLAY: block; VERTICAL-ALIGN: bottom; CURSOR: pointer" height="17" src="..." width="16" />
<IMG style="VERTICAL-ALIGN: top; CURSOR: pointer" height="17" src="..." width="16" />
</DIV>
</DIV>
</DIV>
</DIV></FORM></BODY></HTML>
This code is being generated by a control in a separate library. So here's the actual code creating it in my .aspx page.
<blah:blahControl ID="control" runat="server" />
Ok, it's edited slightly but thats a whole lot more HTML than I had before. The div I was referring to as "parentDiv" before is called "ctl00_BodyContentPlaceHolder_UserControl" up there. That code includes the div in question, it's sibling, parent, grandparent and children. It's almost a direct copy from firebug.
Update:
I should have mentioned this is being done in IE 7. It seemed to work fine one time in Firefox, but it's returning 0 now. Does this provide any new insights of possible work-arounds or anything?
... You all must think I'm nuts.
Update:
Some styling...
.TransparentBg
{
background-color: white;
filter:alpha(opacity=50);
-moz-opacity:0.5;
-khtml-opacity: 0.5;
opacity: 0.5;
}
.Foreground
{
position: absolute;
top: 0px;
}
解决方案 Are you sure it's not a Heisenbug? If you are setting the height somewhere programmatically and then trying to read it soon later, there is a chance DOM would not have updated.
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