As an example of the usefulness, I'll use my recently completed book of small potatoes (wisdom of the ancients) from thepointless.com. With each wise guy quote, we see markup in the following format, which renders a voting widget, with the help of some fancy JavaScript:
<tpdc:voter method='/ajax/pointlisting_vote' record_id='37' vote='1'
fb_like_url='http://www.thepointless.com/pointlistings?id=37'>
<tpdc:vote>vote<tpdc:vote>
<tpdc:unvote>unvote<tpdc:unvote>
+<tpdc:count>1<tpdc:count>
<tpdc:voter>
(Rather the post the full script that does the magic here, I'll be using some trivial simplified JavaScript here for conciseness. You can take a peek at it in action if you're interested.)
To prevent Internet Explorers 7 and 8 from giving us the silent treatment come script-time, our custom tags need to live in a namespace. (Other browsers, as far as I know, ignore the namespace altogether.) And the namespace must be defined in the opening html tag:
<html xmlns:tpdc="http://www.thepointless.com/ns/tpdc">
Now, as you might imagine, a little JavaScript magic is needed to work with these nodes gracefully. And although a touch hacking, it may not be as hackish as you'd expect! As seen on the thepointless.com, here is the function we use to grab these nodes and "import" their attributes correctly:
var getNodes = function(n, q) {
try {
// i think "r" stands for "return" here. // in any event, our first step is to try to find the nodes // by their full names -- that is, with the namespace.
var r = n['getElementsByTagName'](q);
if (r.length < 1) { // ... and if we don't find anything, omit the namespace, // if present.
var p = q.split(":");
if (p.length == 2) {
r = n['getElementsByTagName'](p[1]);
}
}
// import attributes, for each node
for (var i = 0; i < r.length; i++) {
// for each attribute in r[i] // first, make sure we're not attempting to RE-import attributes.
var ri = r[i];
if (!ri.__attributes_imported) {
// so, we basically iterate through each attribute and // "re-attach" it to the node directly. seems silly, but // it allows our scripts to operate on these attributes // later much more naturally.
for (var ai = 0; ai < ri.attributes.length; ai++) {
var att = ri.attributes[ai];
if (!ri[att.name]) {
ri[att.name] = att.value;
}
}
ri.__attributes_imported = true;
}
}
// and finally, give that list of nodes back.
return r;
} catch (e) {
return [];
}
} // getNodes()This getNodes() implementation works in recent versions of Chrome, Firefox, Safari, and IE7+ (not tested in IE6). One-off use of the function works similarly to (but not exactly like) the normal getElementByTagName() function. So, if we want to work with all the tpdc:voter nodes, we could do this:
// get an array of tpdc:voter nodes.
var voterNodes = getNodes(document, "tpcd:voter");
// for each one, let's add an onclick event that simply displays
// the method attribute.
for (var i = 0; i < voterNodes.length; i++) { // to be clear, the "this" here is the node itself
voterNodes[i].onclick = function() { alert(this.method); }
}Pretty simple. And working with child nodes is just as easy. Suppose we want to loop through all the tpdc:voter nodes and make each tpdc:count node with a value of 10 or more bold. Now, with this trivial example, we could do this globally, like so:
// get all the tpdc:count nodes.
var countNodes = getNodes(document, "tpdc:count");
// make each one with an innerHTML value >= 10 bold
for (var i = 0; i < countNodes.length; i++) {
if (parseInt(countNodes[i].innerHTML) >= 10) {
countNodes[i].style.fontWeight = 'bold';
}
}Or, we can work within the context of a single tpdc:voter node, as we might in a voter node's class method. A trivial example again, but this works as expected:
// assume we already have a tpdc:voter node, voterNodevar countChildren = getNodes(voterNode, 'tpdc:count');// act on all tpdc:count nodes found.
for (var ci = 0; ci < countChildren.length; ci++) {
if (parseInt(countChildren[ci].innerHTML) >= 10) {
countChildren[ci].style.fontWeight = 'bold';
}
}Neat.
But, we're not done yet. What we really want is the ability to treat these custom tags like instances of a real class. And we can! We can define a namespace (empty object) with some classes (functions) and bind them semi-automagically to the DOM nodes.
Let's consider a TPDC namespace with two very simple classes:
// the namespace
var TPDC = {};
// class SimpleTPDC.Simple = function() {
// we can do things at object "instantiation" time
this.innerHTML = "Simple";
} // class TPDC.Simple()
// class LessSimple
TPDC.LessSimple = function() { // we can also define object methods this.makeSimple = function() { this.innerHTML = "Simple"; } // TPDC.LessSimple.makeSimple()
this.onClick = function() {
this.makeSimple();
} // TPDC.LessSimple.onClick() this.innerHTML = "Less Simple";
} // class TPDC.LessSimple()Simple. And so is binding our whole TPDC "namespace" to the appropriate document nodes:
for (var k in TPDC) {
var tpdc_nodes = getNodes(document, 'tpdc:' + k);
for (var i = 0; i < tpdc_nodes.length; i++) {
TPDC[k].apply(tpdc_nodes[i]);
}
}And, if we want to stuff our getNodes() function stuffed neatly away in a shared library, we can also add a convenient little binder method:
var BindNS = function(ns_name, parent) {
// "find" the namespace within its parent, given its name
var p = parent || this;
var ns = p[ns_name];
// apply the class constructors to the document nodes
for (var k in ns) {
var ns_nodes = getNodes(document, ns_name.toLowerCase() + ":" + k.toLowerCase());
for (var i = 0; i < ns_nodes.length; i++) {
ns[k].apply(ns_nodes[i]);
}
}
} // BindNS()And then bind our simple TPDC class with one line:
BindNS('TPDC');And at this point, any tags in our document that look like these will operate as though they're instances of our Simple and LessSimple classes:
<tpdc:simple>weeeeee...</tpdc:simple>
<tpdc:lesssimple>...eeeeee!</tpdc:lesssimple>
They also operate as generic DOM nodes too, of course. Your JavaScript classes are, in many respects, subclasses of the Node class.
Two things to remember though:
1. Most browsers ignore the namespace. So, this approach doesn't grant you an ability, so far as I know, to create namespaces with identical class names. You can work around this by including the namespace again as a prefix in your class names if you need to.
and
2. It's invalid markup! It's served up with a text/html content type and an HTML5 doctype, which explicitly forbids tag namespaces. So, you might even call it grossly invalid! That said, of all the custom tag variations I tested, this syntax actually provided the most consistent behavior.
In any event, I like the way this works. I can simplify and minimize both my markup and my script using this approach. And I definitely plan on playing with it more. One thing I'm pondering is an elegant way to automagically attach custom child tags to custom-tag parents in a helpful and meaningful way.
So, if anyone has any thoughts on that (or any of this), I'd be interested in your feedback.
And of course, I encourage you to check out the working examples of this concept at thepointless.com, starting with the book of small potatoes!
Wee!
UPDATE: There's now a building custom tags in html5 and javascript, part 2!
Wow. This really made my day. Thanks a lot!
ReplyDeleteJavascript Training in Chennai | HTML5 Online Training
JavaScript Training Courses | Javascript Online Training | Angular 2 Training in Chennai
JavaScript Online Training JavaScript Online Training JQuery Online Training JQuery Online Training
ReplyDeleteJavaScript Course | HTML5 Online Training
This is an awesome post. Really very informative and creative contents. This concept is a good way to enhance knowledge. I like it and help me to development very well. Thank you for this brief explanation and very nice information. Well, got good knowledge.
ReplyDeleteWordPress development company in Chennai
become a new player in the casino good top online casinos I understood, I understood that on this site, luck will smile at me
ReplyDeleteAwesome article. It is so detailed and well formatted that i enjoyed reading it as well as get some new information too..
ReplyDeleteOracle DBA Online Training
The knowledge of technology you have been sharing thorough this post is very much helpful to develop new idea. here by i also want to share this.
ReplyDeletemsbi online training
Resources like the one you mentioned here will be very useful to me ! I will post a link to this page on my blog. I am sure my visitors will find that very useful
ReplyDeleteTableau online training
I appreciate your efforts because it conveys the message of what you are trying to say. It's a great skill to make even the person who doesn't know about the subject could able to understand the subject . Your blogs are understandable and also elaborately described. I hope to read more and more interesting articles from your blog. All the best.
ReplyDeletemsbi online training
Thanks for such a great article here. I was searching for something like this for quite a long time and at last I’ve found it on your blog. It was definitely interesting for me to read about their market situation nowadays.
ReplyDeleteSql server dba online training
Thank you for benefiting from time to focus on this kind of, I feel firmly about it and also really like comprehending far more with this particular subject matter. In case doable, when you get know-how, is it possible to thoughts modernizing your site together with far more details? It’s extremely useful to me.
ReplyDeleteReactJS Online Training
Thanks for this informative post. Nice blog.
ReplyDeleteminnesota website design
Faribault web design
I appreciate for your a good job and this post gives very useful information. Keep it up...!
ReplyDeleteExcel Training in Chennai
Excel classes in Chennai
Tableau Training in Chennai
Oracle Training in Chennai
Job Openings in Chennai
Pega Training in Chennai
Linux Training in Chennai
Spark Training in Chennai
Embedded System Course Chennai
Soft Skills Training in Chennai
Excel Training in T Nagar
I would definitely thank the admin of this blog for sharing this information with us. Waiting for more updates from this blog admin.
ReplyDeleteRPA Training in Chennai
Robotic Process Automation Certification
Robotic Process Automation Training
DevOps Training in Chennai
Azure Training in Chennai
VMware Training in Chennai
RPA Training in Porur
RPA Training in OMR
RPA Training in Adyar
RPA Training in Anna Nagar
Thanks for sharing Great info… learning driving from experienced instructors help you to learn driving very fast. Driving School Melbourne
ReplyDelete
ReplyDeleteWhen you feel any kind of body pain, it is best if you go to the doctor for treating it. Sometimes body pain can be the symptom of some serious disease. Sometimes body pain attacks us suddenly because of which you may not able to get the help of the doctor. In those situations, to get quick and effective pain relief, you can take the help of painkillers though they cannot cure your pain. As your painkiller, choose Tramadol 50 mg which is very effective. This painkiller is available in the market with the name of Ultram. To use this painkiller, you can get it easily. Buy Tramadol online and get this painkiller at an affordable price.
Buy Tramadol online
Nice article very helpful
ReplyDeleteairtel recharge list
Howdy! I could have sworn I’ve been to this blog before but after looking at many of the posts I realized it’s new to me. Regardless, I’m certainly delighted I discovered it and I’ll be book-marking it and checking back often!
ReplyDeleteTech geek
This blog contains useful information. Thank you for deliverying this usfull blog..
ReplyDeleteSpoken English Classes in Bangalore
Spoken English Classes in Chennai
English Speaking Course in Bangalore
Best Spoken English Classes in Bangalore
Spoken English in Bangalore
Spoken English Classes in Marathahalli
AWS Training in Bangalore
Data Science Courses in Bangalore
DevOps Training in Bangalore
DOT NET Training in Bangalore
Amazing Post. keep update more information.
ReplyDeleteSelenium Training in Chennai
Selenium Training in Bangalore
Selenium Training in Coimbatore
Selenium Course in Bangalore
Best Selenium Training in Bangalore
Selenium training in marathahalli
Selenium training in Btm
Ethical Hacking Course in Bangalore
Tally Course in Chennai
live draw hk banyak terdapat perbedaan dari situs2 penyedia live hk ini. Sedikit saran apabila anda setiap harinya mengikuti live draw hk kami pastikan selalu menggunakan situs live hk yang kami rekomendasikan saja. Termasuk juga untuk live draw sgp ataupun live sgp alternatif ini.
ReplyDeleteThanks for sharing such a great information. Its really nice and informative sql training
ReplyDeleteand ms sql server tutorial.
Poker online situs terbaik yang kini dapat dimainkan seperti Bandar Poker yang menyediakan beberapa situs lainnya seperti http://62.171.128.49/hondaqq/ , kemudian http://62.171.128.49/gesitqq/, http://62.171.128.49/gelangqq/, dan http://62.171.128.49/seniqq. yang paling akhir yaitu http://62.171.128.49/pokerwalet/. Jangan lupa mendaftar di panenqq
ReplyDelete