, due to the fact that it’s smaller and isn’ t being used elsewhere) and then hiding it from view with text-indent:-999em.
Creating an icon font can be a complex and time-consuming process. While font editors can carry out hinting automatically, the best results are achieved manually.
Unless you’re adept at creating your own fonts, you’re restricted to what is available in the font. However, fonts like Pictos will cover the most common needs, and icons are most effective when they’re using familiar conventions.
The main complaint about using fonts for icons is that it can mean adding a meaningless character to our markup. The good news is that we can overcome this by using one of two methods – CSS generated content or the data-icon attribute – in combination with the :before and :after pseudo-selectors, to keep our markup minimal and meaningful.
Our simple markup looks like this:
View Basket
Note the multiple class attributes. Next, we’ll import the Pictos font using the @font-face web fonts property in CSS:
@font-face {
font-family: 'Pictos';
src: url('pictos-web.eot');
src: local('☺'),
url('pictos-web.woff') format('woff'),
url('pictos-web.ttf') format('truetype'),
url('pictos-web.svg#webfontIyfZbseF') format('svg');
}
This rather complicated looking set of rules is (at the time of writing) the most bulletproof way of ensuring as many browsers as possible load the font we want. We’ll now use the content property applied to the :before pseudo-class selector to generate our icon. Once again, we’ll use those multiple class attribute values to set common icon styles, then specific styles for .basket. This helps us avoid repeating styles:
.icon {
font-family: 'Pictos';
font-size: 22px:
}
.basket:before {
content: ""$"";
}
What does the :before pseudo-class do? It generates the dollar character in a browser, even when it’s not present in the markup. Using the generated content approach means our markup stays simple, but we’ll need a new line of CSS, defining what letter to apply to each class attribute for every icon we add.
data-icon is a new alternative approach that uses the HTML5 data- attribute in combination with CSS attribute selectors. This new attribute lets us add our own metadata to elements, as long as its prefixed by data- and doesn’t contain any uppercase letters. In this case, we want to use it to provide the letter value for the icon. Look closely at this markup and you’ll see the data-icon attribute.
View Basket
We could add others, in fact as many as we like.
Favourites
History
Location
Then, we need just one CSS attribute selector to style all our icons in one go:
.icon:before {
content: attr(data-icon);
/* Insert your fancy colours here */
}
By placing our custom attribute data-icon in the selector in this way, we can enable CSS to read the value of that attribute and display it before the element (in this case, the anchor tag). It saves writing a lot of CSS rules. I can imagine that some may not like the extra attribute, but it does keep it out of the actual content – generated or not.
This could be used for all manner of tasks, including a media player and large simple illustrations. See the demo for live examples. Go ahead and zoom the page, and the icons will be crisp, with the exception of the examples that use -webkit-background-clip: text as mentioned earlier.
Finally, it’s worth pointing out that with both generated content and the data-icon method, the letter will be announced to people using screen readers. For example, with the shopping basket icon above, the reader will say “dollar sign view basket”. As accessibility issues go, it’s not exactly the worst, but could be confusing. You would need to decide whether this method is appropriate for the audience. Despite the disadvantages, icon fonts have huge potential.",2011,Jon Hicks,jonhicks,2011-12-12T00:00:00+00:00,https://24ways.org/2011/displaying-icons-with-fonts-and-data-attributes/,code
188,Don't Lose Your :focus,"For many web designers, accessibility conjures up images of blind users with screenreaders, and the difficulties in making sites accessible to this particular audience. Of course, accessibility covers a wide range of situations that go beyond the extreme example of screenreader users. And while it’s true that making a complex site accessible can often be a daunting prospect, there are also many small things that don’t take anything more than a bit of judicious planning, are very easy to test (without having to buy expensive assistive technology), and can make all the difference to certain user groups.
In this short article we’ll focus on keyboard accessibility and how careless use of CSS can potentially make your sites completely unusable.
Keyboard Access
Users who for whatever reason can’t use a mouse will employ a keyboard (or keyboard-like custom interface) to navigate around web pages. By default, they will use TAB and SHIFT + TAB to move from one focusable element (links, form controls and area) of a page to the next.
Note: in OS X, you’ll first need to turn on full keyboard access under System Preferences > Keyboard and Mouse > Keyboard Shortcuts. Safari under Windows needs to have the option Press Tab to highlight each item on a webpage in Preferences > Advanced enabled. Opera is the odd one out, as it has a variety of keyboard navigation options – the most relevant here being spatial navigation via Shift+Down, Shift+Up, Shift+Left, and Shift+Right).
But I Don’t Like Your Dotted Lines…
To show users where they are within a page, browsers place an outline around the element that currently has focus. The “problem” with these default outlines is that some browsers (Internet Explorer and Firefox) also display them when a user clicks on a focusable element with the mouse. Particularly on sites that make extensive use of image replacement on links with “off left” techniques this can create very unsightly outlines that stretch from the replaced element all the way to the left edge of the browser.
Outline bleeding off to the left (image-replacement example from carsonified.com)
There is a trivial workaround to prevent outlines from “spilling over” by adding a simple overflow:hidden, which keeps the outline in check around the clickable portion of the image-replaced element itself.
Outline tamed with overflow:hidden
But for many designers, even this is not enough. As a final solution, many actively suppress outlines altogether in their stylesheets. Controversially, even Eric Meyer’s popular reset.css – an otherwise excellent set of styles that levels the playing field of varying browser defaults – suppresses outlines.
html, body, div, span, applet, object, iframe ... {
...
outline: 0;
...
}
/* remember to define focus styles! */
:focus {
outline: 0;
}
Yes, in his explanation (and in the CSS itself) Eric does remind designers to define relevant styles for :focus… but judging by the number of sites that seem to ignore this (and often remove the related comment from the stylesheet altogether), the message doesn’t seem to have sunk in.
Anyway… hurrah! No more unsightly dotted lines on our lovely design. But what about keyboard users? Although technically they can still TAB from one element to the next, they now get no default cue as to where they are within the page (one notable exception here is Opera, where the outline is displayed regardless of stylesheets)… and if they’re Safari users, they won’t even get an indication of a link’s target in the status bar, like they would if they hovered over it with the mouse.
Only Suppress outline For Mouse Users
Is there a way to allow users navigating with the keyboard to retain the standard outline behaviour they’ve come to expect from their browser, while also ensuring that it doesn’t show display for mouse users?
Testing some convoluted style combinations
After playing with various approaches (see Better CSS outline suppression for more details), the most elegant solution also seemed to be the simplest: don’t remove the outline on :focus, do it on :active instead – after all, :active is the dynamic pseudo-class that deals explicitly with the styles that should be applied when a focusable element is clicked or otherwise activated.
a:active { outline: none; }
The only minor issues with this method: if a user activates a link and then uses the browser’s back button, the outline becomes visible. Oh, and old versions of Internet Explorer notoriously get confused by the exact meaning of :focus, :hover and :active, so this method fails in IE6 and below. Personally, I can live with both of these.
Note: at the last minute before submitting this article, I discovered a fatal flaw in my test. It appears that outline still manages to appear in the time between activating a link and the link target loading (which in hindsight is logical – after activation, the link does indeed receive focus). As my test page only used in-page links, this issue never came up before. The slightly less elegant solution is to also suppress the outline on :hover.
a:hover, a:active { outline: none; }
In Conclusion
Of course, many web designers may argue that they know what’s best, even for their keyboard-using audience. Maybe they’ve removed the default outline and are instead providing some carefully designed :focus styles. If they know for sure that these custom styles are indeed a reliable alternative for their users, more power to them… but, at the risk of sounding like Jakob “blue underlined links” Nielsen, I’d still argue that sometimes the default browser behaviours are best left alone. Complemented, yes (and if you’re already defining some fancy styles for :hover, by all means feel free to also make them display on :focus)… but not suppressed.",2009,Patrick Lauke,patricklauke,2009-12-09T00:00:00+00:00,https://24ways.org/2009/dont-lose-your-focus/,code
326,Don't be eval(),"JavaScript is an interpreted language, and like so many of its peers it includes the all powerful eval() function. eval() takes a string and executes it as if it were regular JavaScript code. It’s incredibly powerful and incredibly easy to abuse in ways that make your code slower and harder to maintain. As a general rule, if you’re using eval() there’s probably something wrong with your design.
Common mistakes
Here’s the classic misuse of eval(). You have a JavaScript object, foo, and you want to access a property on it – but you don’t know the name of the property until runtime. Here’s how NOT to do it:
var property = 'bar';
var value = eval('foo.' + property);
Yes it will work, but every time that piece of code runs JavaScript will have to kick back in to interpreter mode, slowing down your app. It’s also dirt ugly.
Here’s the right way of doing the above:
var property = 'bar';
var value = foo[property];
In JavaScript, square brackets act as an alternative to lookups using a dot. The only difference is that square bracket syntax expects a string.
Security issues
In any programming language you should be extremely cautious of executing code from an untrusted source. The same is true for JavaScript – you should be extremely cautious of running eval() against any code that may have been tampered with – for example, strings taken from the page query string. Executing untrusted code can leave you vulnerable to cross-site scripting attacks.
What’s it good for?
Some programmers say that eval() is B.A.D. – Broken As Designed – and should be removed from the language. However, there are some places in which it can dramatically simplify your code. A great example is for use with XMLHttpRequest, a component of the set of tools more popularly known as Ajax. XMLHttpRequest lets you make a call back to the server from JavaScript without refreshing the whole page. A simple way of using this is to have the server return JavaScript code which is then passed to eval(). Here is a simple function for doing exactly that – it takes the URL to some JavaScript code (or a server-side script that produces JavaScript) and loads and executes that code using XMLHttpRequest and eval().
function evalRequest(url) {
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState==4 && xmlhttp.status==200) {
eval(xmlhttp.responseText);
}
}
xmlhttp.open(""GET"", url, true);
xmlhttp.send(null);
}
If you want this to work with Internet Explorer you’ll need to include this compatibility patch.",2005,Simon Willison,simonwillison,2005-12-07T00:00:00+00:00,https://24ways.org/2005/dont-be-eval/,code
314,Easy Ajax with Prototype,"There’s little more impressive on the web today than a appropriate touch of Ajax. Used well, Ajax brings a web interface much closer to the experience of a desktop app, and can turn a bear of an task into a pleasurable activity.
But it’s really hard, right? It involves all the nasty JavaScript that no one ever does often enough to get really good at, and the browser support is patchy, and urgh it’s just so much damn effort. Well, the good news is that – ta-da – it doesn’t have to be a headache. But man does it still look impressive. Here’s how to amaze your friends.
Introducing prototype.js
Prototype is a JavaScript framework by Sam Stephenson designed to help make developing dynamic web apps a whole lot easier. In basic terms, it’s a JavaScript file which you link into your page that then enables you to do cool stuff.
There’s loads of capability built in, a portion of which covers our beloved Ajax. The whole thing is freely distributable under an MIT-style license, so it’s good to go. What a nice man that Mr Stephenson is – friends, let us raise a hearty cup of mulled wine to his good name. Cheers! sluurrrrp.
First step is to download the latest Prototype and put it somewhere safe. I suggest underneath the Christmas tree.
Cutting to the chase
Before I go on and set up an example of how to use this, let’s just get to the crux. Here’s how Prototype enables you to make a simple Ajax call and dump the results back to the page:
var url = 'myscript.php';
var pars = 'foo=bar';
var target = 'output-div';
var myAjax = new Ajax.Updater(target, url, {method: 'get', parameters: pars});
This snippet of JavaScript does a GET to myscript.php, with the parameter foo=bar, and when a result is returned, it places it inside the element with the ID output-div on your page.
Knocking up a basic example
So to get this show on the road, there are three files we need to set up in our site alongside prototype.js. Obviously we need a basic HTML page with prototype.js linked in. This is the page the user interacts with. Secondly, we need our own JavaScript file for the glue between the interface and the stuff Prototype is doing. Lastly, we need the page (a PHP script in my case) that the Ajax is going to make its call too.
So, to that basic HTML page for the user to interact with. Here’s one I found whilst out carol singing:
Easy Ajax
As you can see, I’ve linked in prototype.js, and also a file called ajax.js, which is where we’ll be putting our glue. (Careful where you leave your glue, kids.)
Our basic example is just going to take a name and then echo it back in the form of a seasonal greeting. There’s a form with an input field for a name, and crucially a DIV (greeting) for the result of our call. You’ll also notice that the form has a submit button – this is so that it can function as a regular form when no JavaScript is available. It’s important not to get carried away and forget the basics of accessibility.
Meanwhile, back at the server
So we need a script at the server which is going to take input from the Ajax call and return some output. This is normally where you’d hook into a database and do whatever transaction you need to before returning a result. To keep this as simple as possible, all this example here will do is take the name the user has given and add it to a greeting message. Not exactly Web 2-point-HoHoHo, but there you have it.
Here’s a quick PHP script – greeting.php – that Santa brought me early.
Season's Greetings, $the_name!"";
?>
You’ll perhaps want to do something a little more complex within your own projects. Just sayin’.
Gluing it all together
Inside our ajax.js file, we need to hook this all together. We’re going to take advantage of some of the handy listener routines and such that Prototype also makes available. The first task is to attach a listener to set the scene once the window has loaded. He’s how we attach an onload event to the window object and get it to call a function named init():
Event.observe(window, 'load', init, false);
Now we create our init() function to do our evil bidding. Its first job of the day is to hide the submit button for those with JavaScript enabled. After that, it attaches a listener to watch for the user typing in the name field.
function init(){
$('greeting-submit').style.display = 'none';
Event.observe('greeting-name', 'keyup', greet, false);
}
As you can see, this is going to make a call to a function called greet() onkeyup in the greeting-name field. That function looks like this:
function greet(){
var url = 'greeting.php';
var pars = 'greeting-name='+escape($F('greeting-name'));
var target = 'greeting';
var myAjax = new Ajax.Updater(target, url, {method: 'get', parameters: pars});
}
The key points to note here are that any user input needs to be escaped before putting into the parameters so that it’s URL-ready. The target is the ID of the element on the page (a DIV in our case) which will be the recipient of the output from the Ajax call.
That’s it
No, seriously. That’s everything. Try the example. Amaze your friends with your 1337 Ajax sk1llz.",2005,Drew McLellan,drewmclellan,2005-12-01T00:00:00+00:00,https://24ways.org/2005/easy-ajax-with-prototype/,code
315,Edit-in-Place with Ajax,"Back on day one we looked at using the Prototype library to take all the hard work out of making a simple Ajax call. While that was fun and all, it didn’t go that far towards implementing something really practical. We dipped our toes in, but haven’t learned to swim yet.
So here is swimming lesson number one. Anyone who’s used Flickr to publish their photos will be familiar with the edit-in-place system used for quickly amending titles and descriptions on photographs. Hovering over an item turns its background yellow to indicate it is editable. A simple click loads the text into an edit box, right there on the page.
Prototype includes all sorts of useful methods to help reproduce something like this for our own projects. As well as the simple Ajax GETs we learned how to do last time, we can also do POSTs (which we’ll need here) and a whole bunch of manipulations to the user interface – all through simple library calls. Here’s what we’re building, so let’s do it.
Getting Started
There are two major components to this process; the user interface manipulation and the Ajax call itself. Our set-up is much the same as last time (you may wish to read the first article if you’ve not already done so). We have a basic HTML page which links in the prototype.js file and our own editinplace.js. Here’s what Santa dropped down my chimney:
Edit-in-Place with Ajax
Edit-in-place
Dashing through the snow on a one horse open sleigh.
So that’s our page. The editable item is going to be the called desc. The process goes something like this:
Highlight the area onMouseOver
Clear the highlight onMouseOut
If the user clicks, hide the area and replace with a