Posts tagged javascript

Dynamic enum fields in nested association forms in Rails Admin

4

We’ve had a few projects at Panoptic Development recently that made use of the RailsAdmin gem. Out of the box, RA satisfied about 95% of what we needed to do to complete each project, but there were a few edge requirements that we either had to make do without or find workarounds for. Don’t get me wrong, RA is a wonderful utility for quickly spinning up an administrative area for your Rails app. It’s loaded with really slick bells-and-whistles, and it has an incredibly flexible DSL for configuration. However, there are a few things it just doesn’t seem to be able to handle as-is and for which I’ve searched high and low for solutions for the last 9 months. I’m happy to report that I finally cracked one of these problems, and it wasn’t even all that complicated in the end.

(more…)

A note about synchronous xmlhttp requests and Firefox

0

Since I just spent the better part of Friday debugging this problem and then the better part of Friday night Googling for a work around, it’s worth noting that there is a “bug” in the Firefox implementation of the xmlHTTPRequest object when using it for synchronous calls (i.e. the rest of the script pauses and waits for the request to complete, unlike typical asynchronous AJAX calls). When using the xmlhttp object in a synchronous fashion, Firefox does not process the onreadystatechange handler. Thus, any libraries that are dependent on this (for running post processing functions for example) will fail to work under these conditions. Interestingly, having the Firebug extension installed causes the object to behave properly. So a secondary note is to always test your apps in a “clean” instance of Firefox.

Here are the details that I came across, along with a work around: Lukav’s Weblog » Blog Archive » Firefox firebug and synchronos calls problem.

I’ve also set up a set of tests to demonstrate the problem. Try in both Firefox and IE to see the differences.

* This post was originally published on June 5, 2007 at http://www.csb7.com/blogs/whyblogwhy/2007/06/05/a_note_about_synchronous_xmlhttp_request

IE getElementById Bug Strikes Again

0

I was burned by the document.getElementById() may return incorrect element in IE and Opera bug again today. This time though it was particularly bothersome as I spent the better part of the afternoon trying to figure out why I couldn’t access the length property of the value of a textarea element in IE when the same code worked fine in Firefox. I mean, getting the length of a value of any form element through JavaScript usually isn’t like rocket science.

<textarea id="description" name="description">Here is some text</textarea>

<script type="text/javascript">
var myElement = document.getElementById('description');
alert(myElement.value.length); //alert: 17
</script>

Every time I tried to execute that code in IE it would complain that 'value.length' is null or not an object.

After a whole crap load of debugging I finally tracked it down to the fact that IE was actually referencing the <meta name=”description”> tag in the head section of the page. Yeah, see even though the function is getElementById, IE still thought I meant the element with the name attribute equal to “description”. Or as my brother put it in a comment to the original post (before the comments were wiped in the great Data Loss of ’06), maybe IE thought I was calling the getJustAboutAnythingIFeelLike() function…

Damn you IE for making me have to change my ID attributes to suite your leisurely implementation of the DOM!

* This post was originally published on April 5, 2007 at http://www.csb7.com/blogs/whyblogwhy/2007/04/05/ie_getelementbyid_bug_strikes_again

Dear Ecma, how about standardizing your date functions, eh?

0

Dear Ecma,

I would just like to point out how completely asinine your JavaScript Date object implementation is. How did so many of it’s member functions come to operate in such a non-intuitive way in relation to each other?

Why does getDate() return the day of the month instead of the date itself, while getDay() returns the day of the week and not the day of the month?

Why does getMonth() return a value from 0-11, but getDate() returns a value from 1-31?

Do you know how utterly confusing that is???

Frustrated,
Me

* This post was originally published on March 22, 2007 at http://www.csb7.com/blogs/whyblogwhy/2007/03/22/dear_ecma_how_about_standardizing_your_d

document.getElementById() may return incorrect element in IE and Opera

0