Super simple chainable JavaScript Object for events, selecting, and add/remove CSS classes and HTML elements.

gs.js

var gs = {

  
	/***********************/
	/* Class Manipulation */
	/***********************/

	addClass :  function(el, clsName) {
		var tmp;

		if (!gs.hasClass(el,clsName)) { 
			tmp = el.className + " " + clsName; 
			el.className = gs.trim(tmp); 
		}
		return this;
	},

	removeClass : function(el, clsName) {
		if (gs.hasClass(el,clsName)) {
			var reg = new RegExp('(\\s|^)'+clsName+'(\\s|$)');
			el.className = gs.trim(el.className);
		}
		return this;
	},

	hasClass : function(el,clsName) {
		return el.className.match(new RegExp('(\\s|^)'+clsName+'(\\s|$)'));
	},

	toggleClass : function(el, clsName) {
		if (gs.hasClass(el, clsName)) {
			gs.removeClass(el, clsName);
		} else {
			gs.addClass(el, clsName);
		}
		return this;
	},


	/***************************/
	/* Element Manipulation */
	/**************************/

	addElement : function (obj) {
		var el, txt, parent, prop;
		
		if (!obj.tag) { obj.tagName = 'div'; } else { obj.tagName = obj.tag.toLowerCase(); }
		el = document.createElement(obj.tagName);
		delete obj.tagName;
		for (prop in obj ) {
			prop = prop.toLowerCase();
			switch(prop) {
				case 'text' :
					el.appendChild(document.createTextNode(obj.text));
					break;
				case 'class':
					gs.addClass(el,obj['class']);
					break;
				default:
					el[prop] = obj[prop];
			}
		}
		return el;
	},

	removeElement : function (obj) {
		var parent;
		parent = obj.parentNode;
		parent.removeChild(obj);
		return this;
	},


	/***************************/
	/* Event Management     */
	/**************************/

	addEvent : function (obj) {
		var el = obj.el , evt = obj.event, callback = obj.callback, bubble = obj.allowBubble || false;

    if (el.addEventListener) { 
      el.addEventListener(evt,callback,bubble);
		} else if (el.attachEvent) {
			el["e"+evt+callback]=callback;
        el[evt+callback] = function() { el["e"+evt+callback](window.event);};
        el.attachEvent("on"+evt,el[evt+callback]);
		}
		return this;
	},

	removeEvent : function (obj) {
		var el = obj.el , 
			evt = obj.event, 
			callback = obj.callback, 
			bubble = obj.allowBubble || false;

		if(el.removeEventListener) {
			el.removeEventListener(evt, callback, bubble);
		} else if(el.detachEvent) {
			el.detachEvent("on" + evt, el[evt+callback]);
			el[evt + callback] = null;
			el["e" + evt + callback] = null;
		}
		return this;
	},

	triggerEvent : function (obj) {
		var e, el= obj.el, evt = obj.event;

    if (document.createEvent) {
      e = document.createEvent("HTMLEvents");
      e.initEvent(evt, true, true);
    } else {
      e = document.createEventObject();
      e.eventType = evt;
    }
    e.eventName = evt;
    if (document.createEvent) {
      el.dispatchEvent(e);
    } else {
      el.fireEvent("on" + e.eventType, e);
    }
		return this;	
	},


	/************************/
	/* Helper Functins       */
	/************************/

	trim : function (txt) {
		return txt.replace(/^\s+|\s+$/g,"");
	},

	getID : function(sel) {
		if (!document.querySelector) {
			return document.getElementByID(sel.replace("#",''));
		} 
		return document.querySelector(sel);
	},

	get : function(sel) {
		var tmp=sel.charAt(0);

		if (tmp === '#') { return gs.getID(sel); }
		if (document.querySelectorAll) {
			return document.querySelectorAll(sel);
		} else {
			if( tmp !== '.' ) {
				return document.getElementsByTagName(sel);
			}
			return document.getElementsByClassName(sel.replace('.',''));
		}
		return undefined;
	}

};

Need to check for support of classList and use those functions instead for supported browsers

if('classList' in document.createElement('a')) {
// use classList API
}