Encosia - ASP.NET, AJAX, jQuery, and more

Setting the value of a datetime-local input with JavaScript

JavaScript, Mobile, UI By . Updated February 28, 2015

While they haven’t gained much traction on the desktop, HTML5’s new input types are great when you’re developing for mobile. Whether you use them in a mobile-friendly website or a hybrid app built with Cordova, most mobile devices will complement those regular HTML inputs with task-appropriate keyboard layouts or even show native interfaces in some cases.

Though these new inputs are pretty handy, they do still have a few rough edges. In fact, I ran into a very frustrating issue while trying set the value of a datetime-local input just today.

In this post, I’ll show you the correct syntax to set the value of a datetime-local input, and how to set it to the current date and time, while correctly accounting for the user’s time zone.
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Using btn-block with Bootstrap 3 dropdown button groups

Bootstrap, CSS, UI By . Posted October 8, 2014


I recently found myself wanting to combine Bootstrap 3’s full-width btn-block button with its split button dropdown component in the same button group (as seen in the screenshot above). As it turned out, it wasn’t as straightforward as you might expect. So, I want to briefly share the solution I found to make that work.
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Use jQuery to extract data from HTML lists and tables

JavaScript, jQuery, UI By . Updated March 31, 2011

A question that I’ve been seeing more frequently these days is how to extract a JavaScript object from an HTML list or table, given no data or information other than the markup. It’s not ideal to work backwards from HTML, but sometimes you just don’t have a lot of choice in the matter.

Whether you’re enhancing legacy elements that have been generated on the server-side or want to parse the output of a third-party DHTML widget, there are a variety of situations where converting HTML to raw data is a legitimate need. You may have seen iterative solutions to this problem before. However, nested looping code gets messy fast, doesn’t feel much like idiomatic jQuery, and certainly isn’t as concise as you’d probably like.

Luckily, one of JavaScript’s lesser-known utility methods and jQuery’s implementation of it can improve the situation quite a bit. In this post, I’m going to show you how to use this method, jQuery’s cross-browser solution, and how to use it to extract data objects from arbitrary HTML lists and tables.

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jQuery Templates, composite rendering, and remote loading

JavaScript, jQuery, UI By . Updated December 4, 2010

In my last post about jQuery Templates, I showed you how to use template composition to build a template out of simple sub-templates. These composite templates are a great way to address the complexity that creeps into real-world UIs, as they inevitably grow and become more intricate. However, one feature missing from my last example was the ability to store those composite templates in external files and load them asynchronously for rendering.

I’ve described how to accomplish that with single templates in the past, using jQuery’s AJAX utilities and a particular usage of tmpl(). Unfortunately, remotely loading a group of composite templates from a single file is not quite as simple, and the technique I’ve described previously will not work.

Not to worry though, it’s still relatively easy.

In this post, I’ll show you how to move a group of composite templates to an external file, how to load and render them with jQuery Templates, and how to take advantage of an expected benefit to improve separation of concerns.

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Composition with jQuery Templates: Why and How

JavaScript, jQuery, UI By . Updated November 11, 2010

I doubt anyone was happier than I was to see that support for composite template rendering was added to jQuery Templates during the interim between the first community proposal and its recent release. If you’re a regular reader, you might remember that I personally lobbied for that functionality back in May, based on how I’ve used jTemplates’ similar #include feature.

Since then, a common question I’ve received amounts to: “Great, but why?”

I think that’s natural, because template composition is one of those things that can seem obscure until you put it to work for the first time. From that point onward, you’ll begin to see the structure of your client-side templates in a different light. Simplifying your templates into smaller logical parts and then combining those parts to create the desired end result is a powerful approach. It’s terrific for making large templates more approachable and maintainable over the lifetime of an application.

In this post, I want to show you an example of a scenario that template composition is well suited to, a couple ways that jQuery Templates’ {{tmpl}} feature can be used to simplify that scenario, and a bonus advantage that the composition approach provides even after the template has been rendered.

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Using external templates with jQuery Templates

JavaScript, jQuery, UI By . Posted October 5, 2010

Now that jQuery Templates is official and definitely will not include remote template loading, I wanted to publish a quick guide on implementing that yourself. As I mentioned previously, there’s a handy interaction between jQuery Templates’ API and jQuery’s AJAX methods that makes this easier than you might expect.

In this post, I’ll show you how to use a plain string as a template, how to asynchronously load an external template file as a string, and how to render it with jQuery Templates once it’s loaded.

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Don’t let jQuery’s $(document).ready() slow you down

jQuery, Performance, UI By . Posted August 18, 2010

jQuery’s $(document).ready() event is something that you probably learned about in your earliest exposure to jQuery and then rarely thought about again. The way it abstracts away DOM timing issues is like a warm security blanket for code running in a variety of cold, harsh browser windows.

Between that comforting insurance and the fact that deferring everything until $(document).ready() will never break your code, it’s understandable not to give much thought to its necessity. Wrapping $(document).ready() around initialization code becomes more habit than conscious decision.

However, what if $(document).ready() is slowing you down? In this post, I’m going show you specific instances where postponing startup code until the document’s ready event slows perceived page load time, could leave your UI needlessly unresponsive, and even causes initialization code to run slower than necessary.

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A few thoughts on jQuery templating with jQuery.tmpl

General, JavaScript, jQuery, UI By . Updated November 8, 2010

I spent some quality time with Dave Reed’s latest revision of John Resig’s jQuery.tmpl plugin recently, migrating a small project from jTemplates. Since both the jQuery team and Microsoft team have requested feedback on jQuery.tmpl, I decided to write about my experience using it (as I am wont to do with these templating proposals).

Overall, jQuery.tmpl is a great step in the right direction. It’s small, it’s simple, and it’s fast. Overloading append() to allow the append(Template, Data) syntax is phenomenal. That approach feels more like idiomatic jQuery than anything else I’ve used, including jTemplates.

However, if this template rendering engine is going to succeed broadly, I feel there’s one important feature still missing. Additionally, there are a couple ancillary features that are present in the current proposal, but should be protected.

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Emulate ASP.NET validation groups with jQuery validation

AJAX, ASP.NET, JavaScript, jQuery, UI By . Updated August 5, 2011

In my most recent post, I demonstrated a workaround to allow using the jQuery validation plugin with WebForms pages. The basic idea was to trigger validation only on submissions that occurred within a single logical form, instead of catching submissions anywhere on WebForms’ all-encompassing physical form.

This approach worked fine for a single logical form, but wasn’t robust enough when handling validation for multiple logical forms on a single page. Additionally, it did not properly handle the enter key, allowing users to (perhaps accidentally) slip past validation if they simply hit the enter key within a TextBox.

In this post, we will continue by refining the solution from last time. So, if you haven’t read the previous post, familiarize yourself with it first. Specifically, this post will cover how to implement an analogue of WebForms’ ValidationGroup, use that to independently validate multiple form regions, handle the enter key, and refactor the final solution to minimize duplicated code.

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Using jQuery validation with ASP.NET WebForms

AJAX, ASP.NET, jQuery, UI By . Updated November 24, 2009

Validation Sticker

You’ve probably noticed that Jörn Zaefferer’s jQuery validation plugin has been gaining momentum in the ASP.NET community lately. Between Microsoft’s implied endorsement via ASP.NET MVC 2.0 integration and the plugin’s recent inclusion on the Microsoft AJAX CDN, adoption is only increasing. Unfortunately for those who don’t or can’t use ASP.NET MVC yet, using the validation plugin within WebForms applications can be tricky.

Because the WebForms Postback model requires that the entire page be contained within a single form element, form submissions that shouldn’t trigger validation are likely. ASP.NET’s built-in validation controls solve this with ValidationGroups and the CausesValidation property, but that doesn’t help if you’d prefer to use the jQuery validation plugin.

However, there are a couple relatively easy workarounds that make it possible to use the jQuery validation plugin on WebForms pages, without re-architecting the page or its forms. In this post, I’ll show you why the WebForms page structure is a problem, how to make jQuery validation work with it, and an example of implementing those workarounds.

Note: I want to preface this by saying that you should never rely entirely on client-side validation. The jQuery validation plugin can be a great replacement for the client-side part of the ASP.NET Validators, but it is not a complete replacement on its own. Use responsibly!

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