CSSplus
CSSplus is a collection of CSS Reprocessor plugins that dynamically update CSS variables.
The plugins are designed to be used in tandem, though it's possible to pick and choose which plugins you want to include in each project.
Included are the following plugins:
- Cursory: mouse/touch cursor variables
- Scrollery: scroll position variables
- Selectory: a selector resolver
- Varsity: scoped variables
Usage
NPM
If you are using NPM you can include all CSSplus plugins by including the entire package:
const cssplus = require('cssplus')This will import all CSSplus plugins and make them available to be used in your own code as:
cssplus.cursory()cssplus.scrollery()cssplus.selectory()cssplus.varsity()
But if you want to include the plugins individually, you can use the module/submodule syntax:
const selectory = require('cssplus/selectory')And this means the Selectory plugin is available to be used in your code as:
selectory()Global JavaScript
To include CSSplus plugins globally (outside of a bundler like Webpack or Browserify) you must include a <script> tag to each plugin you want to use. If you want to include just Selectory for example you would include just the one file like this:
<script src=cssplus/selectory.js></script>To include all CSSplus plugins, you'll need to include links to the following files:
<script src=cssplus/cursory.js></script>
<script src=cssplus/scrollery.js></script>
<script src=cssplus/selectory.js></script>
<script src=cssplus/varsity.js></script>Cursory: mouse/touch cursor variables
Cursory is a CSS reprocessor that makes the following JS values available as CSS variables:
cursorXcursorYinnerWidthinnerHeightclicked
These can be used as CSS variables with the following names:
--cursorX--cursorY--innerWidth--innerHeight--clicked
These variables are updated at the following events:
mousemovetouchmove
In addition, the --clicked variable is changed from 0 to 1 between the mousedown and touchstart events and the corresponding mouseup or touchend events. This allows you to use the var(--clicked) ratio as a 1 or 0 in your CSS calc() functions, or as a value for opacity:; fairly easily.
To run Cursory whenever you want, use the cursory() function in JS.
To make an element like div follow the cursor position when using cursory, use CSS with variables like this:
div {
width: 10px;
height: 10px;
position: fixed;
background: black;
top: calc(var(--cursorY) * 1px);
left: calc(var(--cursorX) * 1px);
}Test available at: test/cursory.html
Scrollery: scroll position variables
Scrollery is a CSS reprocessor that makes the following JS values available as CSS variables for any element you tell the plugin to watch:
scrollWidthscrollHeightscrollLeftscrollTop
To have scrollery watch an element, you need to give that element a unique identifier, as well as add the data-scrollery attribute. The plugin will use either the value of the data-scrollery attribute, or else the value of the id (if defined) for an element.
By default, Scrollery will watch 0 elements. If you add a data-scrollery attribute to either the <html> or <body> element it will attach an event listener for the scroll event on the window, otherwise if you add the data-scrollery attribute to other elements it will add a scroll listener to that element.
To run Scrollery whenever you want, use the scrollery() function in JS.
<div id=example data-scrollery></div>And the following example are both equivalent, and resolve to a name of example:
<div data-scrollery=example></div>Once the plugin is aware of an element to watch, and the unique name of that element, it will make the above values available in the following format: --name-value, for example:
--example-scrollWidth--example-scrollHeight--example-scrollTop--example-scrollLeft
Test available at: test/scrollery.html
Selectory: a selector resolver
Selectory is a CSS reprocessor that resolves selectors using JS. This plugin will read CSS selectors that end with a [test] attribute and use JavaScript to determine whether or not to apply that style to elements matching the other part of that selector. For example, the JS test 1 == 1 will always resolve to true, so a selector written for div[test="1 == 1"] {} will always apply to each div element.
By default, Selectory will reprocess selectors by watching the following events:
loadresizeinputclick
To run Selectory whenever you want, use the selectory() function in JS.
Other things you can do with Selectory include:
Apply a rule to a div when it is wider than 300px:
div[test="this.offsetWidth > 300"] {
background: orange;
}Apply a rule to an input when its value="" attribute is greater than 30:
input[test="this.value > 30"] {
background: lime;
}Apply a rule to an input when it has a value="" attribute zero characters long:
input[test="this.value.length == 0"] {
background: purple;
}Apply a rule to an input when its value="" attribute is more than 5 characters long:
input[test="5 < this.value.length"] {
background: turquoise;
}Apply a rule to an h3 element when it contains at least one span element
h3[test="(this.querySelector('span'))"] {
color: red;
}It is limited what selectors you can use with Selectory, things like :hover and pseudo-classes tend not to work as well. As well the parsing only allows for 1 test per selector, and complex selectors may not work as intended. Using selector[test=""] {} with a simple selector is best.
Test available at: test/selectory.html
Varsity: scoped variables
Varsity is a CSS reprocessor that makes the following JS values available as CSS variables for any element you tell the plugin to watch:
offsetWidthoffsetHeightoffsetLeftoffsetTopaspect-ratiocharacterschildrenvalue
By default, Varsity will reprocess selectors by watching the following events:
loadresizeinputclick
To run Varsity whenever you want, use the varsity() function in JS.
To have varsity watch an element, you need to give that element a unique identifier, as well as add the data-varsity attribute. The plugin will use either the value of the data-varsity attribute, or else the value of the id (if defined) for an element.
<div id=example data-varsity></div>And the following example are both equivalent, and resolve to a name of example:
<div data-varsity=example></div>Once the plugin is aware of an element to watch, and the unique name of that element, it will make the above values available in the following format: --name-value, for example:
--example-offsetWidth--example-offsetHeight--example-offsetLeft--example-offsetTop--example-aspect-ratio--example-characters--example-children--example-value
Test available at: test/varsity.html
Demos
For CSSplus demos, check out the CSSPlus demos collection on Codepen.
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