Earlier in the week, I was looking to customize how the Bootstrap typeahead() plugin was rendering the autocomplete options. Surprisingly, looking at the options listed on the plugin there is no way to specify a custom renderer function. Poking around a bit, I ran across this pull request on GitHub it looks like changes to the typehead() plugin have been tabled since it’s going to be replaced in Bootstrap 3.0 anyway.

I didn’t really want to customize our version of Bootstrap for a single page so I went on the hunt looking for a way to customize the renderer without modifying the plugin. Looking at how the typeahead() plugin is instantiated I noticed that a reference to the “Typeahead()” object with the render() method is actually stored using data() for the element it’s activated on. Because of that, it’s actually relatively straightforward to just overwrite the render() method on the specific element that you’ve activated typeahead() on.

The code I ended up with basically looks like:

Anyway, just a fun tidbit. Questions or comments welcome as always.

Posted In: Javascript

Tags: , ,

Earlier this week, I was doing some work on a project that was using Twitter Bootstrap and was exclusively using Glyphicon icon set that ships with Bootstrap. The piece of functionality I was building basically involved allowing the user to rotate an image 90 degrees clockwise or counterclockwise. Looking through the Bootstrap icon set, there’s only a “rotate” icon which would work for the “clockwise” rotate but no analogous icon for a counterclockwise rotation.

I didn’t really want to use a custom icon just for this button and I really wanted to consistently use the “icon-*” class names that natively ship with Bootstrap. I’ve used CSS transforms in the past but I wasn’t sure if they’d work for “background-images”, turns out they actually do. In essence, what that means is that I’d be able to use the same “rotate” image for both the clockwise and counterclockwise icons. The CSS you’ll need to do this is:

And then to use it, you’ll just need HTML that looks like:

Of course, you’ll have to be cognizant that this is only going to work on “modern browsers” (looking at you IE), so if you’re supporting older clients you’ll need to mitigate that.

Posted In: Tips n' Tricks

Tags: ,

Earlier today, I was adding a “slider” UI element to a project that was using Twitter Bootstrap as well as jQuery UI. Although they weren’t designed to work together, the two projects generally stay out of each other’s way since their CSS classes are namespaced pretty well.

Since jQuery UI was already loaded I naturally decided to just use the jQuery UI slider control to power the slider. One of the limitations with the jQuery UI slider is that it has no native way to show the current slider value over the slider handle, as a developer you have to display that number somewhere. Fortunately, the control has the event hooks neccesary to make this happen – specifically the slide event which is triggered everytime the slider is moved.

With Bootstrap also loaded, I decided to try and use the tooltip plugin to dynamically display the current value of the slider above the handle. Getting the initual tooltip setup was pretty straightforward. Check it out here.

But the issue is that even with the “slide” event, the Bootstrap tooltip plugin has no exposed method to force a reposition. The only way to get a tooltip to reposition itself is to hide it and then show it again. Obviously, that’s less than ideal since you get a noticible “jump” as the tooltip is hid and then shown again.

With this issue in mind, I decided to take a look at how the Tooltip plugin actually does the positioning. It turns out it’s really simple, the relevant code is on GitHub. Ok, so its easy to reposition them but how do you get the “right” tooltip div incase you have multiple sliders? Looking through the code, the Tooltip plugin actually uses the jQuery.data() function to store config options and additionally stores a reference to the correct div there. Getting a handle to the correct div is as easy as $(“#slider .ui-slider-handle:first”).data(“tooltip”).$tip

Looking at the actual plugin code, it’s simple enough to just copy that out and use it to reposition the tooltips. Check it out in action at http://jsfiddle.net/cqVPM/7/

Anyway, let me know if you run into any issues in the comments.

Posted In: Demo, jQuery

Tags: , , ,

During the last two years the number of mobile devices has grown at an exponential pace, with one Cisco estimate (http://bit.ly/zVdFJD) predicting more mobile connected devices than people by the end of 2012. Due to this growth, providing a first class mobile web experience has become increasingly important and is now a paramount concern for websites. Union Square Ventures’ Fred Wilson went as far as to point out that new web apps are commonly designed “mobile first web second” (http://bit.ly/gQTtBp)

Within the last year a technique known as “responsive design” has become an increasingly popular way to tackle “mobile vs. desktop” web design issues. There have been several reasons for this rise in popularity which we’ll talk about after an abridged history of the mobile web.

How did we get here? Well it all started with WAP… Back in the dark days of the mobile web, well before the average consumer was accessing the Internet from a cellphone the majority of web content was served via a technology called the Wireless Application Protocol. Even I am to young to really have experienced it in all of its glory but the “Criticisms” page on Wikpedia should convey just how awful it was – http://bit.ly/wWxY2c Big takeaways? Imagine writing websites in XML, oh and it has to validate.

Anyway, fast forward a couple of years and vaguely recognizable devices are slowly starting to come online. From the Nokia Symbians, to Palm, and of course the venerable Blackberry mobile devices are beginning to access the nascent mobile web (yay!). The problem? The browsers on these devices were severely limited in terms of CSS and Javascript support, standards compatibility, and available bandwidth. As a result of these limitations, developers chose to basically develop “stripped down” basic HTML versions of sites to present on mobile devices.

One last trip in the DeLorean and we’re zooming from the initial release of the iPhone during the summer of 2007 to today with thousands of smart phone and tablet models and billions of connected devices. During this period, developers tended to build specific “mobile” sites which were usually an entirely separate HTML/CSS/JS(kinda?) code base from their desktop sites. Understandably, this situation was less than ideal since at the minimum it meant maintaining two code bases and the mobile site often lacked the full functionality of the desktop site. Additionally, as both desktop and mobile browser development rapidly progressed consumers began to expect a consistent experience across their devices.

So how do we address these issues and improve mobile user experience? Enter, “responsive design”. The central tenant of responsive design is that you (the designer/developer) should be able to use the same HTML, CSS, and Javascript to serve devices with different screen sizes and resolutions. The idea is that your layout should be able to respond by adapting the it’s presentation layer depending on any number of factors.

The key technology this process relies upon are Media Queries. Fully adopted by CSS3, media queries allow CSS directives to be conditionally applied depending on the result of a boolean query. In practice, this means a single CSS stylesheet can contain one set of directives for a 480px screen as well as different directives for a 1200px screen. Lets look at an example. If you open http://www.agentvita.com/ and then progressively shrink your browser window you’ll see that the elements dynamically adjust depending on the size of the screen.

Well that’s some history and a quick demonstration, now for some nitty implementation gritty details. Unfortunately, there’s no “magic bullet” to automatically take a standard desktop layout and responsively adapt it for different screen sizes. In my opinion the best approach is to start with a solid framework, keep your markup clean, and of course be cognizant that you’re planning to adapt the layout for different screen sizes. Or if you’re feeling brave, start with the mobile layout first and then progressively enhance the layout as your screen size increases.

Here are some specific resources to get started: