function getFirstElementByClass(className, tagName)
{
	var elems = document.getElementsByTagName(tagName);
	for (i = 0; i < elems.length; i++)
	{
		if (elems[i].className == className)
		{
			return elems[i];
		}
	}
}

function getAllElementsByClass(className, tagName)
{
	var elems = document.getElementsByTagName(tagName);
	var toReturn = new Array();
	var cpt = 0;
	for (i = 0; i < elems.length; i++)
	{
		if (elems[i].className == className)
		{
			toReturn[cpt] = elems[i];
			cpt++;
		}
	}
	
	return toReturn;
}

function emptyElement(elem)
{
	var i;
	while (i = elem.childNodes[0])
	{
		if (i.nodeType == 1 || i.nodeType == 3)
		{
			elem.removeChild(i);
		}
	}
}

function getDocHeight() 
{
    var D = document;
    return Math.max(
        Math.max(D.body.scrollHeight, D.documentElement.scrollHeight),
        Math.max(D.body.offsetHeight, D.documentElement.offsetHeight),
        Math.max(D.body.clientHeight, D.documentElement.clientHeight)
    );
}

function getDocTop() 
{
    var D = document;
    return Math.max(
        Math.max(D.body.scrollTop, D.documentElement.scrollTop),
        Math.max(D.body.offsetTop, D.documentElement.offsetTop),
        Math.max(D.body.clientTop, D.documentElement.clientTop)
    );
}

function setDocTop(top) 
{
    var D = document;
    D.body.scrollTop = top;
	D.documentElement.scrollTop = top;
    D.body.offsetTop = top;
	D.documentElement.offsetTop = top;
    D.body.clientTop = top;
	D.documentElement.clientTop = top;
}