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Skopein - Scoped CSS Stylesheets with element queries and a $this selector
:self {
background: lime;
}
<!DOCTYPE html>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Skopein - Scoped Stylesheets</title>
<link rel="scoped" href="skopein.css" data-selector="input" data-test="this.value.length > 5">
<p>Input tags will go green when their value has more than 5 characters:</p>
<input>
<input>
<input>
<script src="skopein.js"></script>
var skopein = {}
skopein.load = function() {
var link = document.querySelectorAll('link[rel="scoped"]')
for (i = 0; i < link.length; i++) {
var currentLink = link[i]
var stylesheet = ''
if (currentLink.href) {
(function() {
var xhr = new XMLHttpRequest
xhr.open('GET', currentLink.href, true)
xhr.send(null)
xhr.onreadystatechange = function() {
skopein.process(currentLink, xhr.responseText)
}
})()
}
}
}
skopein.process = function(link, stylesheet) {
if (stylesheet) {
var event = link.getAttribute('data-event')
? link.getAttribute('data-event').replace(/ /g, '').split(',')
: ['load', 'resize', 'input', 'click']
for (var j=0; j < event.length; j++) {
if (!link.getAttribute('data-populated')) {
var style = document.createElement('style')
link.parentNode.insertBefore(style, link)
link.setAttribute('data-populated', true)
}
window.addEventListener(event[j], function(e) {
var tag = document.querySelectorAll(link.getAttribute('data-selector'))
var func = new Function('return ' + link.getAttribute('data-test'))
var selector = []
var count = 0
for (var k=0; k<tag.length; k++) {
// process selectors
if (func.call(tag[k])) {
var attr = link.getAttribute('data-selector').replace(/\W+/g, '')
tag[k].setAttribute('data-scoped-' + attr, count)
selector.push('[data-scoped-' + attr + '="' + count + '"]')
count++
} else {
tag[k].removeAttribute('data-scoped-' + attr)
}
}
if (style) {
var css = stylesheet.replace(/:self|\$this/g, selector)
style.innerHTML = css
}
})
}
}
}
window.addEventListener('load', skopein.load)
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