anonymous.js

const UID = {
	_current: 0,
	getNew: function(){
		this._current++;
		return this._current;
	}
};

HTMLElement.prototype.pseudoStyle = function(element, prop, value){
	var _this = this;
	var _sheetId = "pseudoStyles";
	var _head = document.head || document.getElementsByTagName('head')[0];
	var _sheet = document.getElementById(_sheetId) || document.createElement('style');
	_sheet.id = _sheetId;
	var className = "pseudoStyle" + UID.getNew();

	_this.className +=  " "+className;

	_sheet.innerHTML += " ."+className+":"+element+"{"+prop+":"+value+"}";
	_head.appendChild(_sheet);
	return this;
};