Can i use attributes of element to create style rules? - html

Question

I'm noot good in english, so the title may seem a bit odd.
I want to use css function attr() like this:
I mean i have a container <div> and an inner <div> that i want to have width depending on data-width attribute. For example this would be great, but this doesnt work:
<div class="container">
<div data-width="70%">
</div
</div>
.container {
width: 600px;
height: 200px;
}
.container div {
width: attr(data-width);
height: 100%;
}
Is there any noJS way to use attributes like that?
UPDATE: Guys convinced me that the JS is the only way to do this :)
That's not a big problem (but that's bad. CSS, why youre so illogical? Is the difference between content:attr(data-width) and width: attr(data-width) so big ?).
One of the guys had an idea to go through the all elements with jQuery.
That's ok, but it is very... local? Don't know how to say it in english.
Anyway, i remaked his code a little bit and here it is:
allowed = ['width','color','float'];
$(document).ready(function () {
$('div').each(function (i, el) {
var data = $(el).data(),style = '';
if (!$.isEmptyObject(data)) {
$.each(data, function (attr, value) {
if (allowed.indexOf(attr) != - 1) {
style += attr + ': ' + value + '; ';
}
})
if (style.length != 0) {
$(el).attr('style', style);
}
}
})
})
Idea is simple:
1. We suppose that style we want to add to an element is the only one. I mean there are no scripts that will try to add some other styles,
2. We create an array of allowed attribute names, we need to avoid using wrong names at the style attribute, for example style="answerid: 30671428;",
3. We go through each element, save its data attributes in an object, check if object is empty, and if not - check every attribute if it is allowed, create a string that contains all styles that we need, and - finally - add our style string to the element as the content of style attribute.
That's all, thanks everybody

Answer 1

I would not advise to use CSS alone since it will not allow you to do what you're looking for... instead use a scripting language (in my case jQuery) to accomplish this functionality for you like so: jsFiddle
jQuery
jQuery(document).ready(function(){
var dataElem; // to store each data attribute we come accross
jQuery('div').each(function(){ //loop through each div (can be changed to a class preferably)
dataElem = jQuery(this); //get the current div
if(dataElem.data('width')){ //make sure it exists before anything further
dataElem.width(dataElem.data('width')); //set the element's width to the data attribute's value
dataElem.css("background-color", "yellow");
}
});
});
HTML
<p>The links with a data-width attribute gets a yellow background:</p>
<div>
w3schools.com
</div>
<div class="me" data-width="50"> <!-- change value to see the difference -->
disney.com
</div>
<div>
wikipedia.org
</div>
Notes on the above:
each, data, width.

Answer 2

Instead of doing data-width, use a class attribute. An html tag can have mutliple classes separated by spaces, so if you wanted to be very precise, you could set up as many classes as you need. For instance:
<div class="w70 h100">
</div>
Then in your css:
.w70{
width: 70%;
}
.h100{
height: 100%;
}
And so on.

Answer 3

Is there any noJS way to use attributes like that?
No, you cannot use CSS to set the width of the element to it's data-width attribute. CSS does not allow for this as attr() is only currently available for the CSS content property which is only available on css pseudo elements (::before and ::after).
How can you achieve this with as little javascript as possible?
This is extremely easy to do using the native host provided DOM API.
Select the elements using Document.querySelectorAll().
Iterate the elements and apply the styles using Element.style which can be retrieved from the data-width attribute using Element.dataset
(Demo)
var items = document.querySelectorAll('#container div'), item, i;
for(i = 0; (item = items[i]); i++) item.style.width = item.dataset.width;