A Simple Query Syntax for CSS Element Queries
The goal of QSS is to define a simple syntax for specifying element queries by adding a new ending part between a CSS selector list and the block of rules that help define the breakpoints when those rules are to apply.
Normally in CSS you have something like this:
selectorList { block }
We are going to add a new part for our query between the selector list and the block where we will store instructions for when the rule should apply.
selectorList <query> { block }
Because this exists as a new part between the selector list and the block of rules, if you have a list of selectors like h1, h2, h3, h4, h5, h6 {} you only need to add the query once after the selector list is complete, like h1, h2, h3, h4, h5, h6 <query> {} rather than h1 <query>, h2 <query>, h3 <query>, ….
This document describes two different formats for expressing element queries for individual CSS rules, one using an if-based structure, and another that uses the @ symbol to declare when it should apply.
if
width | height | characters | children | xscroll | yscroll
< | below | under | <= | max | == | equals | >= | min | > | above | over
div if width above 500 {}
input if characters under 1 {}
@
< | below | under | <= | max | == | equals | >= | min | > | above | over
width | height | characters | children | xscroll | yscroll
div @ above 500 width {}
input @ under 1 characters {}
In both phrase formats the whitespace between tokens is optional, this means that if you prefer to think about these as @above or @min you can express them that way. The following should all equivalent:
div if width >= 500 {}
div if width >=500 {}
div if width min 500 {}
div @min 500 width {}
div@min500width{}
div @ >=500 width {}
The queries parsed by QSS would be split into the following pieces:
And these could also be used to construct Element Queries for other syntaxes like:
Essentially QSS acts as a syntax to abstract away writing these: Useful Tests for JS-powered Styling
This repository contains a working proof of concept of a plugin to parse and read QSS syntax. In order to use this plugin you just need to include QSS on the page where you want it to display:
<script src=qss.js></script>
Then you're able to add queries written in QSS syntax to your site using one of the following methods: a <style> tag, a <link> tag with type=text/qss set, or a <script> tag with a type of text/qss either inline or linked externally using a src="" attribute:
<style type="text/qss"></style>
<link type="text/qss" href=stylesheet.qss rel=stylesheet>
<script type="text/qss"></script>
<script type="text/qss" src=stylesheet.qss></script>