patbenatar/jquery-nested_attributes

Note: Instead of using the method in this card, you probably want to use ActiveType's nested attributes which is a much more refined way of doing this.

The attach...

Say we want …

• to create a Gallery that has a name and has_many :images, which in turn have a caption
• to offer the user a single form to create a gallery with any number of images
• immediate uploads with a progress bar per image
• a snapp...

jQuery's removeClass removes the given class string from an element collection. If you want to remove multiple/unknown classes matching a given pattern, you can do that.

For example, consider a DOM node for the following HTML. We'll reference i...

This guide shows how to create an AngularJS application that consumes more and more memory until, eventually, the browser process crashes on your users.

Although this guide has been written for Angular 1 originally, most of the advice is relevant...

• To retrieve only unique combinations of the selected attributes: You can omit rows, where all selected columns are equal with the DISTINCT statement.
• To retrieve the group wise maximum of certain columns: You can keep only one record fo...

This card describes four variants, that add a more intuitive workflow when working with nested attributes in Rails + Unpoly:

1. Without JS
2. With HTML template and JS
3. [With...

Here are some popular mistakes when using nested forms:

• You are using fields_for instead of form.fields_for.
• You forgot to use accepts_nested_attributes in the containing model. Rails won't complain, but nothing will work. In particular...

If validations failed for a record, and you want to find out if a specific validation failed, you can leverage ActiveModel's error objects.
You rarely need this in application code (you usually just want to print error messages), but it can be u...

Recent IRB versions include a multi-line autocomplete which may be helpful to novice users but can be distracting.

Cycling through options works by pressing the Tab key (as usual), and for some methods you also get some kind of documentation, tho...

When you set both a record's association and that association's foreign key attribute, Rails does not realize you are talking about the same thing. The association change will win in the next save, even if the foreign key attribute was changed a...