Is it possible to auto-select the text in a PRE tag without the use of Javascript?
No, you have to use scripting to achieve that. There might be some accessibility tools out there that does that for you on form elements (like autofocusing on the first input field in a form) but probably not for arbitrary elements and depending on your actual use-case this might not be an option for you (if it even exists).
And to my knowledge the whole range selection in JavaScript is still not standardized AND implemented by all relevant browser manufactures in that standardized way ;-) ( http://www.quirksmode.org/dom/range_intro.html )
Related
Is there any harm if custom tags are used and created based on one's choice?
like the one below
<hello>hi there!</hello>
I tried using CSS
hello{
color:red;font-family:arial;
}
The above code works
I have used the above and also can add CSS. is there any harm of doing this, or the CSS features these won't support?
This is purely out of curiosity so don't suggest CSS edits or solutions please.
Why you can't make up elements
It is not valid HTML. Therefore how it behaves will be unpredictable.
It may work in some browsers, currently, but if any of your users visit your site on a different browser, they may get a totally different experience. Further to that, support could be dropped, or change at any time without warning.
Other options for custom elements
It is actually possible to define your own Document Type Definition (DTD), however that too is not a good idea.
Your best bet is to either stick with normal, well-supported HTML elements (see here for list of valid elements), or to use a web component framework, such as Vue, Angular or React, for custom elements/ components.
Don't forget, that you can add the class attribute (as well as others) to any element for styling, so for your use-case, there isn't any need to have additional elements.
I am creating a search form that has two elements an input field and a button. The input field does not have an label associated with it.
To make the field more accessible I can add <label for="searchfield">Search</label> and visually hide it so it will e.g. be accessible for screenreaders.
I could also add aria-label="search" to the input field and leave the input field without an label.
I have tested with "Voice Over" on a Mac and I get the same result/output. My question is are these approaches equivalent? Or is one approach better than the other one?
Here is a pen.
In the absence of having any knowledge of the site (how are other form fields labeled?) or the audience (what is their skill level or tech profile?), I approach these questions with a couple parameters:
The rules of ARIA (the first rule may apply here)
Progressive enhancement
That being said, I often code a page without ARIA and without CSS (as that may get blocked, chunked, etc) and make sure it is accessible.
That means I code a <label>. Then I visually hide it. If the CSS breaks, all is still well. If the user's screen reader does not support ARIA, all is still well. As an aside, if you think all screen readers of your users support ARIA, I encourage you to do to a tech assessment of users (local blind associations are a good start in the absence of any real users). Many people still run older versions of browsers and SRs.
For sighted users, I make sure I lean on contextual clues, like a clear search icon (or the word) in the button (as Unor references). Or maybe a placeholder with appropriate contrast (though you could use the <label> as a visual placeholder with some CSS trickery to hide it on focus).
If your submit button uses SVG, then I would be folding ARIA into that given the inconsistent support around SVG alternative text methods.
FWIW, I am also not a fan of the title attribute, partly because of inconsistent accessible name calculation and partly because I think it looks meh.
So, to answer your questions:
My question is are these approaches equivalent?
No, but the distance between them is shrinking.
Or is one approach better than the other one?
That depends on context we do not have.
Using aria-label is preferable to relying on CSS to visually hide a label element.
(Related Technique: Using aria-label to provide an invisible label where a visible label cannot be used)
But note that you don’t have to provide a label for a search form that only consists of the search field and the submit button. Assuming that you use a button labeled with something like "Search", it already makes clear which purpose the text field has.
(Related Technique: Using an adjacent button to label the purpose of a field)
In that case, while it doesn’t need a label, it should still get a name. One way to provide a name is to use the title attribute on the input element. The Technique Using the title attribute to identify form controls when the label element cannot be used shows this (a search form without label, with title attribute on input) in example 3.
I believe that aria-label="search" is the correct approach, as it produces cleaner markup (i.e. no unnecessary label tag) and no need for CSS to set visibility of the label - like in this example.
I believe visually hiding a label using CSS is a somewhat 'hacky' way to approach the problem, whereas ARIA is the standard for accessible markup, so it should be the obvious choice for situations like this.
On the other hand, it would be worth ensuring all browsers you intend to support can use ARIA correctly, and if not, it may be worth using the label approach to ensure compatibility across all browsers. Although, I think the support these days is pretty good, so that should not be a common scenario.
Given current HTML5 specs that allows creating custom HTML elements (as long as their name contains a dash), and the fact that Web Components seem to be a feature that's here to stay, I'd like to know why is creating your own custom HTML elements frowned upon?
Note, that I'm not asking whether to use Web Components - which are still a moving target, and even with great polyfills like Polymer might not be ready for production yet. I'm asking about creating your own custom HTML tags and styling them, without attaching any JS APIs to them.
Short answer: I haven't heard any very compelling reasons to avoid them.
However, here are some recurring arguments I've heard made:
Doesn't work in old IE (just document.createElement("my-tag"); should fix that).
Global namespace clashes (same applies to class names, and custom elements in general).
CSS selector performance (doh, this is just about the last thing you should worry about).
Separation of functionality, meaning and presentation. This is actually the only argument I've heard that IMHO has any valid basis to it. You're of course better off with semantic HTML (search engines and all that), but if you were going to use a div for it otherwise, I don't see why you couldn't use a custom tag instead.
One of the arguments against custom tags is their implied incompatibility with screen readers. This issue can be resolved with WAI-ARIA attributes.
There exists an issue in IE11, which breaks table layout if a custom element without display property is inserted inside a table cell. Check the plunker code. Therefore, it's the safest to declare all new elements explicitly, for example like so:
new-element {
display: block;
}
I am seeing some attribute I have never seen before in a div tag. I haven't touch html for a while but googling the attribute didn't return much useful info.
<div dataquery="#item_1306" comp="box.components.Flashplayer" id="box_Flashplayer_2" propertyquery="#box_Flashplaye_2" class="box_Flashplaye_style2"...
My question is, do you know what are these "dataquery" "comp" and "propertyquery" attributes?
Thanks alot folks.
HTML is often enhanced with custom attributes these days, and HTML5 explicitly allows for that. Normally these attributes should be prefixed with "data-", but obviously this is not the case here.
The meaning depends most probably on a script included in the page.
For example, in twitter bootstrap it is common to see attributes like <body data-spy='scroll'> which is than interpreted by a script and allows for monitoring the amount a user scrolls.
When including Facebook like buttons you may have attributes like data-style which controls whether a box, or a button, or hwatever is used.
You can add you own attributes to elements. I don't think theese atributes are standard attributes lika class and name but an attribute that the programmer has added self for some purpose.
Those are not W3C attributes, they have used to perform some task, may be to the lagulage it used and may performance some special tags, But its not best practice because it gives HTML validation errors, better thing is use data-xxxx tag for extra attributes.
More readings.
http://www.javascriptkit.com/dhtmltutors/customattributes.shtml
http://ejohn.org/blog/html-5-data-attributes/
http://html5doctor.com/html5-custom-data-attributes/
Having the HTML of a webpage, what would be the easiest strategy to get the text that's visible on the correspondent page? I have thought of getting everything that's between the <a>..</a> and <p>...</p> but that is not working that well.
Keep in mind as that this is for a school project, I am not allowed to use any kind of external library (the idea is to have to do the parsing myself). Also, this will be implemented as the HTML of the page is downloaded, that is, I can't assume I already have the whole HTML page downloaded. It has to be showing up the extracted visible words as the HTML is being downloaded.
Also, it doesn't have to work for ALL the cases, just to be satisfatory most of the times.
I am not allowed to use any kind of external library
This is a poor requirement for a ‘software architecture’ course. Parsing HTML is extremely difficult to do correctly—certainly way outside the bounds of a course exercise. Any naïve approach you come up involving regex hacks is going to fall over badly on common web pages.
The software-architecturally correct thing to do here is use an external library that has already solved the problem of parsing HTML (such as, for .NET, the HTML Agility Pack), and then iterate over the document objects it generates looking for text nodes that aren't in ‘invisible’ elements like <script>.
If the task of grabbing data from web pages is of your own choosing, to demonstrate some other principle, then I would advise picking a different challenge, one you can usefully solve. For example, just changing the input from HTML to XML might allow you to use the built-in XML parser.
Literally all the text that is visible sounds like a big ask for a school project, as it would depend not only on the HTML itself, but also any in-page or external styling. One solution would be to simply strip the HTML tags from the input, though that wouldn't strictly meet your requirements as you have stated them.
Assuming that near enough is good enough, you could make a first pass to strip out the content of entire elements which you know won't be visible (such as script, style), and a second pass to remove the remaining tags themselves.
i'd consider writing regex to remove all html tags and you should be left with your desired text. This can be done in Javascript and doesn't require anything special.
I know this is not exactly what you asked for, but it can be done using Regular Expressions:
//javascript code
//should (could) work in C# (needs escaping for quotes) :
h = h.replace(/<(?:"[^"]*"|'[^']*'|[^'">])*>/g,'');
This RegExp will remove HTML tags, notice however that you first need to remove script,link,style,... tags.
If you decide to go this way, I can help you with the regular expressions needed.
HTML 5 includes a detailed description of how to build a parser. It is probably more complicated then you are looking for, but it is the recommended way.
You'll need to parse every DOM element for text, and then detect whether that DOM element is visible (el.style.display == 'block' or 'inline'), and then you'll need to detect whether that element is positioned in such a manner that it isn't outside of the viewable area of the page. Then you'll need to detect the z-index of each element and the background of each element in order to detect if any overlapping is hiding some text.
Basically, this is impossible to do within a month's time.