JSFiddle - React, Tailwind, and code Playground

HTML

<textarea></textarea>
<br />
<textarea></textarea>

JavaScript

var cssMap = {
    color: 'color',
    size : 'fontSize',
    fontfamily : 'fontFamily'
}

function applyCSS(selector, qs) {
    var props  = qs.split('&'),
        elems  = document.querySelectorAll(selector),
        styles = {};
    
    for (var i=props.length; i--;) {
        var parts = props[i].split('=');
        styles[cssMap[parts[0]]] = parts[1];
    }
    
    for (var j=elems.length; j--;) {
        for (var style in styles) {
            elems[j].style[style] = styles[style];
        }
    }
    return styles;
}

var url = 'http://www.domain.com/?color=#000&size=32px&fontfamily=serif';

applyCSS('textarea', url.split('?').pop())