Javascript code to recursively search for a element given the element's Id

  • Thread starter Thread starter Cal Who
  • Start date Start date
C

Cal Who

I need Javascript code to recursively search for a element given the
element's Id so that I can modify a elements attributes.

I do not use JQuery but I believe that once when I was searching the
Internet for something else I saw that JQuery has a function called $ that
did just that. And the author showed the Javascript code from that library.
I'm not sure if that is what I need but now that I want it I can't find it.

Bottom line: Can you point to (or supply) Javascript code to recursively
search for a element given it's Id?



Thanks in advance
 
I need Javascript code to recursively search for a element given the
element's Id so that I can modify a elements attributes.

I do not use JQuery but I believe that once when I was searching the
Internet for something else I saw that JQuery has a function called $ that
did just that. And the author showed the Javascript code from that library.
I'm not sure if that is what I need but now that I want it I can't find it.

Bottom line: Can you point to (or supply) Javascript code to recursively
search for a element given it's Id?
Click to expand...
Perhaps you mean something like

var element = document.getElementById('someID');

regards
A.G.
 
You do not need a recursive function to find an element in a document by its id.

Just use

var element = document.getElementById('someID');




Cal Who wrote:

Javascript code to recursively search for a element given the element's Id
22-May-10

I need Javascript code to recursively search for a element given th
element's Id so that I can modify a elements attributes

I do not use JQuery but I believe that once when I was searching th
Internet for something else I saw that JQuery has a function called $ tha
did just that. And the author showed the Javascript code from that library
I am not sure if that is what I need but now that I want it I cannot find it

Bottom line: Can you point to (or supply) Javascript code to recursivel
search for a element given it is Id


Thanks in advance

Previous Posts In This Thread:


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That's what I thought but lost confidence when it returned null in the
following:

<script type="text/javascript">

function SetMargins(id) {

var element = document.getElementById(id);

....

Which is in the .master and the id looks like I'd expect:

id = "ctl00_BottomImageCPH_QQQ"



I called it from and aspx.vb file

<asp:Content ID="Content8" runat="server"
ContentPlaceHolderID="BottomImageCPH">

<script type="text/javascript">

SetMargins('<%=QQQ.ClientID%>');

</script>


<div runat="server" id="QQQ" style="margin-left: 10%; margin-right: 10%;" >

....


Why the null??


Thanks
 
That's what I thought but lost confidence when it returned null in the
following:

<script type="text/javascript">

function SetMargins(id) {

var element = document.getElementById(id);

...

Which is in the .master and the id looks like I'd expect:

id = "ctl00_BottomImageCPH_QQQ"



I called it from and aspx.vb file

<asp:Content ID="Content8" runat="server"
ContentPlaceHolderID="BottomImageCPH">

<script type="text/javascript">

SetMargins('<%=QQQ.ClientID%>');

</script>


<div runat="server" id="QQQ" style="margin-left: 10%; margin-right: 10%;" >

...


Why the null??
Click to expand...
From the second snippet it appears the SetMargins method is being
called as the document is rendered. The document is rendered from top
to bottom. If SetMargins is called before control QQQ is rendered to
the document, the document won't find the control, and
document.getElementById will return null.

You may have to read that last sentence a couple of times ;)

I would suggest attaching a javascript method to the page body's
onload event. That method will be called after the page has been
rendered. From within that method make the call to SetMargins.

regards
A.G.
 
Mark Rae said:
Because of ASP.NET's control ID munging.

var control = document getElementById('<%=MyControl.ClientID%>');
Click to expand...
Help me out here. It seems to me that
calling it from the .vb file using the clientId
is effectively the same.
And the munged string gets passed.

No?

As ways, Thanks
 
Registered User said:
From the second snippet it appears the SetMargins method is being
called as the document is rendered. The document is rendered from top
to bottom. If SetMargins is called before control QQQ is rendered to
the document, the document won't find the control, and
document.getElementById will return null.
Click to expand...
I bet that is why IE8 developer tool only shows the HTML to just befor QQQ.
That's as much as was rendered.

You may have to read that last sentence a couple of times ;)

I would suggest attaching a javascript method to the page body's
onload event. That method will be called after the page has been
rendered. From within that method make the call to SetMargins.
Click to expand...

But there are no events in a content page, is there?
regards
A.G.
Click to expand...


Thanks
 
Mark said:
Because of ASP.NET's control ID munging.

var control = document getElementById('<%=MyControl.ClientID%>');
Click to expand...
He did that, but at the point where his SetMargins function was called.
 
No?
Click to expand...

Yes, but it seems from other replies that you're trying to call the
SetMargins function before the page is completely rendered, which is why
it's not finding the control...
 
Mark Rae said:
Yes, but it seems from other replies that you're trying to call the
SetMargins function before the page is completely rendered, which is why
it's not finding the control...
Click to expand...
True, I just move the call to after the </div> and that seems to have fixed
it. I'm not sure if that is a reliable way.

Thanks
 
Registered User said:
This is true but a solution can be found at
http://www.webreference.com/programming/javascript/onloads/

regards
A.G.
Click to expand...

I moved the call to right after the </div> and that seems to have fixed it.
I'm not sure if that is a reliable way.

Do you think adding an event would be more reliable (say over different
browser types)

In this situation I don't see the "magically change" he referred to
probably because the rendering and change is so close.

In any event I'm saving that link for possible later need- good stuff.

Thanks
 
I moved the call to right after the </div> and that seems to have fixed it.
I'm not sure if that is a reliable way.

Do you think adding an event would be more reliable (say over different
browser types)
Click to expand...
I would use the onload event because the page has been loaded. Leaving
the call in-line with the rendering works but is subject to error if
the mark-up gets re-arranged by someone else. AFAIK all browsers
support the onload event so that should not be an issue.
In this situation I don't see the "magically change" he referred to
probably because the rendering and change is so close.
Click to expand...
If the user could see the change there wouldn't be any magic ;)
In any event I'm saving that link for possible later need- good stuff.
Click to expand...

regards
A.G.
 
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