- From: Dean Edwards <dean@edwards.name>
- Date: Wed, 20 Apr 2005 15:50:02 +0100
Ian Hickson wrote:
> On Wed, 20 Apr 2005, Dean Edwards wrote:
>
>>The use case is a web app that submits data to a hidden iframe. This is
>>common in JSP type backends. The hidden frame then updates the page with
>>new data. Maybe this is just me working on projects that are designed
>>wrong! Anyone else encounter this scenario?
>
>
> So you'd submit to a hidden <iframe> and then disable the main page?
>
Yep. The iframe then unlocks the page when submission is complete.
Forgetting about iframes for a minute. This is analogous to disabling
the entire application (not the chrome). Most GUI apps have this
behavior to some degree.
> In past projects of this nature I used to create a new <iframe> each time
> I submitted something, so there'd be no problem submitting multiple times,
> it would just update the UI multiple times (and if they shouldn't, then I
> would prevent the submission by disabling the entry points to submitting).
>
> More recently I just spawn a new XMLHttpRequest for each submission.
>
For this particular use case there are now better techniques it's true.
>
>>I can't think of one off the top of my head but I do find myself using
>>it. It's certainly handy for passing string references around rather
>>than object references.
>
>
> Wouldn't object references by lighter weight?
>
Sometimes you want to construct eval code. A string reference is the
only way to do this. Here is some sample code from IE7 that disables
unsuccessful form controls on submission:
[code]
elem[i].disabled = true;
setTimeout("document.all." + elem[i].uniqueID + ".disabled=false", 1);
[/code]
To do the same using object references you would have to create a
closure. The string version is easier. As I say, I found myself using
this surprisingly often. But then I do write some pretty freaky code... ;-)
-dean
Received on Wednesday, 20 April 2005 07:50:02 UTC