(function() {

function $(id) {
	return document.getElementById(id);
}

function setStyleDisplay(id, status) {
	$(id).style.display = status;
}

function goTop(a, t) {
	a = a || 0.1;
	t = t || 16;

	var x1 = 0;
	var y1 = 0;
	var x2 = 0;
	var y2 = 0;
	var x3 = 0;
	var y3 = 0;

	if (document.documentElement) {
		x1 = document.documentElement.scrollLeft || 0;
		y1 = document.documentElement.scrollTop || 0;
	}
	if (document.body) {
		x2 = document.body.scrollLeft || 0;
		y2 = document.body.scrollTop || 0;
	}
	var x3 = window.scrollX || 0;
	var y3 = window.scrollY || 0;

	var x = Math.max(x1, Math.max(x2, x3));
	var y = Math.max(y1, Math.max(y2, y3));

	var speed = 1 + a;
	window.scrollTo(Math.floor(x / speed), Math.floor(y / speed));
	if(x > 0 || y > 0) {
		var f = "MGJS.goTop(" + a + ", " + t + ")";
		window.setTimeout(f, t);
	}
}


function getElementsByClassName(className, tag, parent) {
	parent = parent || document;

	var allTags = (tag == '*' && parent.all) ? parent.all : parent.getElementsByTagName(tag);
	var matchingElements = new Array();

	className = className.replace(/\-/g, '\\-');
	var regex = new RegExp('(^|\\s)' + className + '(\\s|$)');

	var element;
	for (var i = 0; i < allTags.length; i++) {
		element = allTags[i];
		if (regex.test(element.className)) {
			matchingElements.push(element);
		}
	}

	return matchingElements;
}

window['MGJS'] = {};
window['MGJS']['$'] = $;
window['MGJS']['setStyleDisplay'] = setStyleDisplay;
window['MGJS']['goTop'] = goTop;
window['MGJS']['getElementsByClassName'] = getElementsByClassName;

})();