Re: XMLHttpRequest and Google Chrome

From	Robbie Brown <rob@example.com>
Newsgroups	comp.lang.javascript
Subject	Re: XMLHttpRequest and Google Chrome
Date	2015-04-14 11:35 +0100
Organization	A noiseless patient Spider
Message-ID	<mgiqfg$1mp$1@dont-email.me> (permalink)
References	<mgedt0$ki9$1@dont-email.me>

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On 12/04/15 19:36, Robbie Brown wrote:
>
>
> Chrome 41.0.2272.118
> Windows 8.1
>
> Chrome 41.0.2272.118
> Ubuntu 12.10
>
> Chrome 26.0.1410.43
> Ubuntu 12.04 LTS
>
> all 64bit
>
> I'm having a problem with asynch' javascript requests in the above
> versions of Chrome on the above platforms. The same code works fine in
> various versions of Firefox and Opera on the above platforms.
>
> The problem is worst on Ubu 12.10, not so bad but annoyingly frequent on
> Win 8.1 and hardly happens at all on Ubu 12.04 LTS
>
> Here's the admittedly old function I call to get an XMLHttpRequest object
>
> function newXMLHttpRequest() {
>
>    var xmlreq = false;
>
>    if (window.XMLHttpRequest) {
>      // Create XMLHttpRequest object in non-Microsoft browsers
>      xmlreq = new XMLHttpRequest();
>
>    }
>    else if (window.ActiveXObject) {
>      try {
>          xmlreq = new ActiveXObject("MSXML2.XMLHTTP.3.0");
>      }
>      catch(e){
>          try {
>            // Try to create XMLHttpRequest in later versions
>            // of Internet Explorer
>            xmlreq = new ActiveXObject("Msxml2.XMLHTTP");
>          }
>          catch (e1) {
>            // Failed to create required ActiveXObject
>            try {
>              // Try version supported by older versions
>              // of Internet Explorer
>              xmlreq = new ActiveXObject("Microsoft.XMLHTTP");
>            }
>            catch (e2) {
>
>              // Unable to create an XMLHttpRequest with ActiveX
>            }
>          }
>        }
>      }
>     return xmlreq;
> }
>
> and here's a function I call when a page is loaded
>
> function getCart(){
>      var req = newXMLHttpRequest();
>       req.onreadystatechange = getReadyStateHandler(req, updateCart);
>       req.open("POST", "common/ManageCart?cartmode=crtget", true);
>       req.setRequestHeader("Content-Type",
> "application/x-www-form-urlencoded");
>       req.send("");
> }
>
> updateCart uses javascript DOM to update the innerHTML property of a <div>
>
> The error in the Chrome javascript console is
>
> Uncaught TypeError: Cannot set property 'innerHTML' of null
>
> Like I say, it's only Chrome that has this problem frequently enough to
> be a problem
>
> Any ideas on what might be causing this problem in Chrome greatly
> appreciated
>
> Thanks
>
> Rob


Oh My, what a mistake ...

Firstly, thanks to everyone who took the time to respond, it's much 
appreciated.

As a reward I'll give you a good laugh

I have two areas that are dynamically updated
A cart snapshot and a compare list snapshot
at one point I had this in <head>

<script type="text/javascript">
    window.onload=getCart;
    window.onload=getCompareList;	
</script>

No, don't laugh ... oh all right then, I suppose I deserve it.

So I changed it to

<script type="text/javascript">
    function loadDynamics(){
       getCart();
       getCompareList();
    }	
</script>

<script type="text/javascript">
    window.onload=loadDynamics;	
</script>

and now, so far, it all seems to work as expected even in the Chrome 
instances that were giving the most trouble. Unless there's another 
howler I've missed of course :-(

There is a fair amount of latency that causes the cart area particularly 
to sometimes show the 'network congestion' message, but it gets there 
eventually ... and users can always click the 'get on with it' button if 
they become impatient.

Such is the price of asynchronism I suppose.


Thanks again


-- 
Not floundering ... just fishing

Thread

XMLHttpRequest and Google Chrome Robbie Brown <rob@example.com> - 2015-04-12 19:36 +0100
  Re: XMLHttpRequest and Google Chrome JJ <jj4public@vfemail.net> - 2015-04-13 12:33 +0700
    Re: XMLHttpRequest and Google Chrome Robbie Brown <rob@example.com> - 2015-04-13 07:41 +0100
  Re: XMLHttpRequest and Google Chrome Martin Honnen <mahotrash@yahoo.de> - 2015-04-13 11:30 +0200
    Re: XMLHttpRequest and Google Chrome Robbie Brown <rob@example.com> - 2015-04-13 11:50 +0100
      Re: XMLHttpRequest and Google Chrome Tim Streater <timstreater@greenbee.net> - 2015-04-13 13:17 +0100
        Re: XMLHttpRequest and Google Chrome Robbie Brown <rob@example.com> - 2015-04-13 13:34 +0100
          Re: XMLHttpRequest and Google Chrome Tim Streater <timstreater@greenbee.net> - 2015-04-13 14:26 +0100
          Re: XMLHttpRequest and Google Chrome Martin Honnen <mahotrash@yahoo.de> - 2015-04-13 16:15 +0200
            Re: XMLHttpRequest and Google Chrome Robbie Brown <rob@example.com> - 2015-04-13 16:03 +0100
              Re: XMLHttpRequest and Google Chrome Martin Honnen <mahotrash@yahoo.de> - 2015-04-13 19:26 +0200
                Re: XMLHttpRequest and Google Chrome "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-04-13 20:23 +0200
          Re: XMLHttpRequest and Google Chrome Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-04-13 15:50 +0100
            Re: XMLHttpRequest and Google Chrome Robbie Brown <rob@example.com> - 2015-04-13 16:10 +0100
              Re: XMLHttpRequest and Google Chrome "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-04-13 17:46 +0200
                Re: XMLHttpRequest and Google Chrome Robbie Brown <rob@example.com> - 2015-04-13 17:28 +0100
                Re: XMLHttpRequest and Google Chrome "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-04-13 19:14 +0200
                Re: XMLHttpRequest and Google Chrome Tim Streater <timstreater@greenbee.net> - 2015-04-13 18:29 +0100
                Re: XMLHttpRequest and Google Chrome Robbie Brown <rob@example.com> - 2015-04-13 18:59 +0100
                Re: XMLHttpRequest and Google Chrome "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-04-13 20:29 +0200
                Re: XMLHttpRequest and Google Chrome Tim Streater <timstreater@greenbee.net> - 2015-04-13 19:34 +0100
                Re: XMLHttpRequest and Google Chrome Robbie Brown <rob@example.com> - 2015-04-13 20:11 +0100
                Re: XMLHttpRequest and Google Chrome "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2015-04-13 20:44 +0200
                Re: XMLHttpRequest and Google Chrome Robbie Brown <rob@example.com> - 2015-04-13 20:21 +0100
                Re: XMLHttpRequest and Google Chrome Denis McMahon <denismfmcmahon@gmail.com> - 2015-04-14 12:43 +0000
                Re: XMLHttpRequest and Google Chrome Robbie Brown <rob@example.com> - 2015-04-14 14:50 +0100
                Re: XMLHttpRequest and Google Chrome Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-04-14 22:51 +0200
                Re: XMLHttpRequest and Google Chrome Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-04-13 22:28 +0200
  Re: XMLHttpRequest and Google Chrome Robbie Brown <rob@example.com> - 2015-04-13 19:23 +0100
    Re: XMLHttpRequest and Google Chrome Tim Streater <timstreater@greenbee.net> - 2015-04-13 19:38 +0100
  Re: XMLHttpRequest and Google Chrome "Leonardo Azpurua" <leonardo@exmvps.org> - 2015-04-13 17:36 -0430
  Re: XMLHttpRequest and Google Chrome Robbie Brown <rob@example.com> - 2015-04-14 11:35 +0100
  Re: XMLHttpRequest and Google Chrome Denis McMahon <denismfmcmahon@gmail.com> - 2015-04-14 11:37 +0000

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