Javascript code to recursively search for a element given the element's Id
in [ASP .NET]
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From: Cal Who on 23 May 2010 08:35 "Registered User" <n4jvp(a)ix.netcom.com> wrote in message news:42qhv51mlka86p7547o6qo2j48nfmcf78t(a)4ax.com... > On Sat, 22 May 2010 20:34:51 -0400, " Cal Who" > <CalWhoNOSPAM(a)roadrunner.com> wrote: > >> >>"Registered User" <n4jvp(a)ix.netcom.com> wrote in message >>news:rbogv5p4i6uotm8qgsr8ajok5b1jhvdd4s(a)4ax.com... >>> On Sat, 22 May 2010 18:19:25 -0400, " Cal Who" >>> <CalWhoNOSPAM(a)roadrunner.com> wrote: >>> >>>>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?? >>>> >>> 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. >>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. >> >>But there are no events in a content page, is there? >> > This is true but a solution can be found at > http://www.webreference.com/programming/javascript/onloads/ > > regards > A.G. 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
From: Registered User on 23 May 2010 11:05
On Sun, 23 May 2010 08:35:45 -0400, " Cal Who" <CalWhoNOSPAM(a)roadrunner.com> wrote: > >"Registered User" <n4jvp(a)ix.netcom.com> wrote in message >news:42qhv51mlka86p7547o6qo2j48nfmcf78t(a)4ax.com... >> On Sat, 22 May 2010 20:34:51 -0400, " Cal Who" >> <CalWhoNOSPAM(a)roadrunner.com> wrote: >> >>> >>>"Registered User" <n4jvp(a)ix.netcom.com> wrote in message >>>news:rbogv5p4i6uotm8qgsr8ajok5b1jhvdd4s(a)4ax.com... >>>> On Sat, 22 May 2010 18:19:25 -0400, " Cal Who" >>>> <CalWhoNOSPAM(a)roadrunner.com> wrote: >>>> >>>>>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?? >>>>> >>>> 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. >>>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. >>> >>>But there are no events in a content page, is there? >>> >> This is true but a solution can be found at >> http://www.webreference.com/programming/javascript/onloads/ >> >> regards >> A.G. > >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) > 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. > 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. > regards A.G. |