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Why use HTML5 tags? [duplicate]
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Why use HTML5 semantic tags like headers, section, nav, and article instead of simply div with the preferred css to it?
I created a webpage and used those tags, but they do not make a difference from div. What is their main purpose?
Is it only for the appropriate names for the tags while using it or more than that?
Please explain. I have gone through many sites, but I could not find these basics.
The Oxford Dictionary states:
semantics: the branch of linguistics and logic concerned with meaning.
As their name says, these tags are meant to improve the meaning of your web page. Good semantics plays an important role the automated processing of documents. This automated processing happens more often than you realize - each website ranking from search engines is derived from automated processing of all the website out there.
If you visit a (well designed) web page, you as the human reader can immediately (visually) distinguish all the page elements and more importantly understand the content. In the top left you see the company logo, next to it is the site navigation, there is a search bar and some text about the company, a link to a product you can buy and a legal disclaimer at the bottom.
However, machines are dumb and cannot do this:
Looking at the same page as you, all the web crawler would see is an image, a list of anchors tags, a text node, an input field and an image with a link on it. At the bottom there is another text node.
Now, how should they know, what part of the document you intended to be the navigation or the main article, or some not-so-important footnote? They can guess by analyzing your document structure using some common criteria which are a hint for a specific element.
E.g. an ul list of internal links is most likely some kind of page navigation and the text at the end of the document is something necessary but not so important to the everyday viewer (the legal disclaimer).
Now imagine instead of a plain div, a nav element would be used – the machine immediately knows what the purpose of this element is:
// machine: okay, this structure looks like it might be a navigation element?
<div><ul><li><a href="internal_link">...</div>
// machine: ah, a navigation element!
<nav><ul><li><a>...</nav>
Now the text inside a main tag – this is clearly the most important information of the page! Over there to the left, that text node, the image and the anchor node all belong together, because they are grouped inside a section tag, and down at the bottom there is some text inside a footer element (they still don't know the meaning of that text, but now they can deduce it's some sort of fine print).
Example:
You, as the user (reading a page without seeing the actual markup), don't care if an element is enclosed in an <i> or <em> tag. In most browsers both of these tags will be rendered identically – as italic text – and as long as it stands out between the surrounding text it serves its purpose.
However, there is a big difference in terms of semantics:
<i> means italic - it's simply a presentational hint for the browser on how to render it (italic) and does not necessarily contain deeper semantic information.
<em> means emphasize - it indicates an important piece of information. Now the browser is not bound to the italic instruction any more, but could render it in italic or bold or underlined or in a different color... For visually impaired persons, the screen readers can raise the voice - whatever method seems most suited in a specific situation to emphasise this important information.
Final thought:
Semantic tags are not the end. There are things like metadata, ontologies, resource description languages which go a step further and help connect data between different web pages and can even help create new knowledge!
E.g. wikipedia is doing a really bad job at semantically presenting data.
https://en.wikipedia.org/wiki/Barack_Obama
https://en.wikipedia.org/wiki/Donald_Trump
https://en.wikipedia.org/wiki/Joe_Biden
All three are persons who at some point in time where president of the USA.
All three articles contain a sidebar that displays these information, and you can compare them (by opening both pages and then switching back and forth), but they are not semantically described.
Instead, if wikipedia used an ontology to describe a person: http://dbpedia.org/ontology/Person
<!-- President is a subclass of Politician which is a subclass of Person -->
<President>
<birthname>Barrack Hussein Obama II</birthname>
<birthdate>1961-08-04</birthdate>
<headOf>country::USA</headOf>
<tenure>2009-01-20 – 2017-01-20</tenure>
</President>
Not only could you (and machines) now directly compare those three directly (on a dynamically generated page!), but you could even create new knowledge, e.g. show a list of all presidents of the United States - quite boring but also cool stuff like who are all the current world leaders, how many female world leaders do we have, who is the youngest leader, how many types of leaders are there (presidents/emperors/queens/dictators), who served the longest, how many of them are taller than 175cm and have brown eyes, etc. etc.
In conclusion, good semantics is super cool (but also – on a technical level – hard to achieve and maintain).
There's a nice little article on HTML5 semantics on HTML5Doctor.
Semantics have been a part of HTML in some form or another. It helps you understand what's happening where on the page.
Earlier when <div> was used for pretty much everything, we still implemented semantics by giving it a "semantic" class name or an id name.
These tags help in proper structuring and understanding of the layout.
If you do,
<div class="nav"></div>
as opposed to,
<nav></nav>
OR
<div class="sidebar"></div>
as opposed to,
<aside></aside>
there's nothing wrong, but the latter helps in providing better readability for you as well as crawlers, readers, etc..
In the div tag you have to give an id which tells about what kind of content it is holding, either body, header, footer, etc.
While in case of semantic elements of HTML5, the name clearly defines what kind of code it is holding, and it is for which part of the website.
Semantic elements are <header>, <footer>, <section>, <aside>, etc.
Related
I have been trying to understand the <figure> element; take a look at this from w3.org:
Self-contained in this context does not necessarily mean independent. For example,each sentence in a paragraph is self-contained; an image that is part of a sentence would be inappropriate for figure, but an entire sentence made of images would be fitting.
How can an image can be part of a sentence? What is this talking about? I have read many explanations, but yet I don't understand why I would want to use this element. What is the purpose of this tag?
According to MDN:
Usually a <figure> is an image, illustration, diagram, code snippet, etc., that is referenced in the main flow of a document, but that can be moved to another part of the document or to an appendix without affecting the main flow.
An example of this (based on one from that same MDN link) might be a code snippet that prints the parts of the browser's navigator in an article about that attribute. You don't need to know the exact code to print that information to understand what is in the navigator, but it can aid the reader's understanding.
Additionally, the <figure> tag allows use of the <figcaption> tag as a child, which is a convenient and accessible way to caption images.
HTML5 semantic tags are cryptic for everyone. Since the concepts are kept abstract and scientific in purpose, I will use a bunch of over-simplification to make it understandable, in spite of HTML5
gurus telling me how wrong I am.
Remember that semantic tags are created to be read by computers, not humans. They exist so that google's scripts (and everyone's scripts, but mainly google and hacker bots) can quickly search for figures and index them. To understand semantic tags, think like a script, not as a human.
"If I was a bot programmed by a hacker, how would I mine figures when crawling my website?"
If we code a script that looks for IMG tags it will end up gathering a bunch of garbage (i.e. icons). What we're interested in is real content, that's what "self-contained content" means: you cut & paste this element from your website into my gallery of mined images in your HTML, and it's useful.
Garbage: icons, decorative images, images created by javascript plugins to prettify things, smileys, etc.
Good finds: charts, photos, diagrams, maps, drawings, etc.
The "Good finds" make sense even if you steal them from your webpage with no context whatsoever, except things like the accompanying "caption" tag. These tags allow crawlers to associate your images with text tags, making categorization easier So you don't want to miss this content.
So we're interested in the figure caption, title, subtitle, whatever, and the figure should wrap all of this. The figure tag is not limited to images; it can contain text, video, audio, code blocks, anything as long as it's part of that "entity" in your document. So the following is a single figure:
Now, in documents like scientific papers you will often find stuff like this:
Although each image makes sense by itself, they make more sense as a group as they are connected by some kind of relationship; sometimes even the order matters (i.e. series of steps, or photos of states something goes through). That's a "sentence of figures" and you want to mine them together or you'll lose valuable information.
Our mining algorithm would have to understand your website's content with some kind of natural-language-processing AI, or it could just gather the FIGURE tags you provide for it. The later is good semantics.
Summarizing, imagine you're the Google AI algorithm mining figures in your code. Write your figure tags to make this script's job easy.
We have inherited a website which we are currently trying to make WCAG2.0 AA compliant
One of the pages is failing the heading-order rule as it has an <h3> and <h4> tags but no prior <h1> or <h2>
We are in the process of adding an <h1> tag (as all pages should have one) but there is no need for an <h2> tag and to amend the <h3> and <h4> would involve a large refactoring of various jQuery code and CSS
Are there any tricks to make the page accessible? I'm loathed to put a hidden <h2> tag in as the screen readers would presumably pick this up. Or do they ignore the hidden tags and the page then becomes compliant?
Are you trying to satisfy WCAG 2.0 AA or are you trying to make the page accessible?
These are usually the same, but sometimes not.
A hidden <h2> would pass WCAG depending on how you hide it. That, however, would not make the page more accessible.
While this may suck, the best, most correct approach is to fix the <h3>s and <h4>s to become correct levels (that is my answer, the rest of this is fluff). Your question might be more appropriate if you instead provide some code samples and ask for tips on how to write a regex or otherwise script these replacements throughout the inherited system.
If you are being told you have no time to do it right, then code examples (or a sample site) might still be helpful to get some guidance.
I really have seen this situation before, and actually have fallen into this trap myself. By applying styles to the h3 and h4, it is possible to make a page look, well, a certain way.
Looking at the point of the header tags however, it is their purpose to add semantics to the document, as we all well know. Is it, therefore, meaningful to have a document outline where there is an h3 but no h2? Screenreaders and other accessibility tools use this header information and some could get confused.
My most influential decision-making point is, "how will the user consume this information?" Will they be able to consume it? Is it meaningful to skip a header level? I initially think not, but please let me know of your differing opinion!
If you really do care about accessibility, giving an empty h2 (even implicitly which is the case when you omit it) might give no clue, in some screen readers, of the announced section to users when they will navigate the outline of the document (1).
That being said, I can't find anywhere (neither WCAG or HTML5 documentation) where it's said that you can't omit one level of headings.
The only official (for HTML5.1) requirement is to use "headings of lower rank" to start new subsections, which should mean that you could use a h3 directly below a h1 but can't use another h1
Even the WCAG is giving an example using omitted ranks saying this example does not intend to prescribe the level for a particular section.
(1) HTML5.1 provides an outline algorithm where we can read about "implied headings" or about the use of the rank when there is an heading content element
I would say the best way to ensure compliance is to refactor the code that is in the javascript/CSS. To hide elements you could use the hidden attribute or aria-hidden.
https://www.paciellogroup.com/blog/2012/05/html5-accessibility-chops-hidden-and-aria-hidden/
I'm following the CodeSchool foundation course now with HTML. Its saying its 'not OK' to not have a <h2> heading as the top one:
we removed the h1 tag and replaced it with an img tag. That's fine, but it also means that our highest level heading right now is an h2 tag, which isn't OK.
Is this going to affect the final product or is it just a design thing?
Nothing will break if there is a h2 and no h1. However, the way computers read websites, is by parsing the HTML. The only way the computer knows that something is a top-level header (h1) is by finding the h1 tag.
The most common reason I can think of at the moment, as to why you want h1 insted of h2, is how search engines index your website. Using a h1, means that the text within the tag is highly relevant to your website, while h2 is not as important (but still more important than h3 for example).
So it's not about what works and don't works, but it's about what things should be. Writing a website, following all the "rules" of HTML, will make it easily parsable by crawlers (programs that parse websites and gather information).
Another, important, reason why your html should be well-structured is for blind people. They use programs that read out text from websites to "read" the website. Having bad semantic/bad structured html might make these programs useless.
Edit:
Sorry, as mentioned, document outline would break, but the website would still be rendered, which is what I was referring to.
The heading elements are used to provide semantic meaning to your content (as most HTML elements do). In addition, people who use assistive technologies, such as screen readers, rely on certain HTML elements to provide information as to how to navigate a page. The heading elements (h1...h6) help to create the page's Document Outline, for which there is a defined specification.
If you were to start with an h2, the outline would be broken.
Just as it makes no sense to stat a report on section 2, you should not start a web page there for the same reason.
SEO
Search Engine Optimalization! If a person searches for, say, "Rubik's Cubes", a search engine will look through their data to see which sites have the string "Rubik's Cubes" (or some substring or related words) on their site.
Now, if your site has the string "Rubik's Cubes" in an <h1> tag, the search engine will understand that this is the entire point of your page, and rank it higher, because it's the title of the entire page!
Meanwhile, if you have it in an <h2> it's probably just some part of the page, and that's fine too, but not AS good.
So while structurally, it makes no difference, think of SEO when you choose which header you use. If you're picking them just based on size, that's a bad idea. Just style them bigger/smaller instead!
When it comes to writing blog markup, I absolutely understand the use of article and section tags. But my masthead sections have two widgets. One has a search engine embedded and the other is marketing copy leading to an FAQ page.
What would be the correct HTML5 markup in this case? How do I mark up widget functionality?
my masthead sections have two widgets. One has a search engine embedded...
A search engine embedded? Do you mean a search field, i.e. a text field into which you can type search terms? For that, you want <input type="search">.
...and the other is marketing copy leading to an FAQ page.
Does this really qualify as a “widget”? If it’s marketing copy “leading” to an FAQ page, that just sounds like a link to me, which has been semantically represented in HTML since version 1 with the <a> element.
HTML is pretty simple, you really don’t want to over-think it. You don’t need specific tags for everything people could possibly give a name to. (What exactly is a “widget”? Isn’t it just a section of the page?) For most things, <section> is fine.
While HTML5 is a big improvement, there's one thing it doesn't fix: The subjectivity of what is considered proper semantics for every situation.
And, I doubt HTML will ever fix that.
If you're already using HTML5 containers for other more obvious parts of the page, I wouldn't sweat these too elements much. You could put the marketing stuff in an aside. Search could be considered a form of nav. But...I don't think bad karma will come your way if you just stick them in a couple of divs, either. ;)
I have seen it a lot in css talk. What does semantically correct mean?
Labeling correctly
It means that you're calling something what it actually is. The classic example is that if something is a table, it should contain rows and columns of data. To use that for layout is semantically incorrect - you're saying "this is a table" when it's not.
Another example: a list (<ul> or <ol>) should generally be used to group similar items (<li>). You could use a div for the group and a <span> for each item, and style each span to be on a separate line with a bullet point, and it might look the way you want. But "this is a list" conveys more information.
Fits the ideal behind HTML
HTML stands for "HyperText Markup Language"; its purpose is to mark up, or label, your content. The more accurately you mark it up, the better. New elements are being introduced in HTML5 to more accurately label common web page parts, such as headers and footers.
Makes it more useful
All of this semantic labeling helps machines parse your content, which helps users. For instance:
Knowing what your elements are lets browsers use sensible defaults for how they should look and behave. This means you have less customization work to do and are more likely to get consistent results in different browsers.
Browsers can correctly apply your CSS (Cascading Style Sheets), describing how each type of content should look. You can offer alternative styles, or users can use their own; as long as you've labeled your elements semantically, rules like "I want headlines to be huge" will be usable.
Screen readers for the blind can help them fill out a form more easily if the logical sections are broken into fieldsets with one legend for each one. A blind user can hear the legend text and decide, "oh, I can skip this section," just as a sighted user might do by reading it.
Mobile phones can switch to a numeric keyboard when they see a form input of type="tel" (for telephone numbers).
Semantics basically means "The study of meaning".
Usually when people are talking about code being semantically correct, they're referring to the code that accurately describes something.
In (x)HTML, there are certain tags that give meaning to the content they contain. For example:
An H1 tag describes the data it contains as a level-1 heading. An H2 tag describes the data it contains as a level-2 heading. The implied meaning behind this is that each H2 under an H1 is in some way related (i.e. heading and subheading).
When you code in a semantic way, you basically give meaning to the data you're describing.
Consider the following 2 samples of semantic VS non-semantic:
<h1>Heading</h1>
<h2>Subheading</h2>
VS a non-semantic equivalent:
<p><strong>Heading</strong></p>
<p><em>Subheading</em></p>
Sometimes you might hear people in a debate saying "You're just talking semantics now" and this usually refers to the act of saying the same meaning as the other person but using different words.
"Semantically correct usage of elements means that you use them for what they are meant to be used for. It means that you use tables for tabular data but not for layout, it means that you use lists for listing things, strong and em for giving text an emphasis, and the like."
From: http://www.codingforums.com/archive/index.php/t-53165.html
HTML elements have meaning. "Semantically correct" means that your elements mean what they are supposed to.
For instance, you definition lists are represented by <dl> lists in code, your abbreviations are <abbr>s etc.
It means that HTML elements are used in the right context (not like tables are used for design purposes), CSS classes are named in a human-understandable way and the document itself has a structure that can be processed by non-browser clients like screen-readers, automatic parsers trying to extract the information and its structure from the document etc.
For example, you use lists to build up menus. This way a screen reader for disabled people will know these list items are parts of the same menu level, so it will read them in sequence for a person to make choice.
I've never heard it in a purely CSS context, but when talking about CSS and HTML, it means using the proper tags (for example, avoiding the use of the table tag for non-tabular data), providing proper values for the class and id that identify what the contained data is (and using microformats as appropriate), and so on.
It's all about making sure that your data can be understood by humans (everything is displayed properly) and computers (everything is properly identified and marked up).