// JavaScript Document
function getElementsByClass(searchClass,node,tag) {
	var classElements = new Array();
	if ( node == null )
		node = document;
	if ( tag == null )
		tag = '*';
	var els = node.getElementsByTagName(tag);
	var elsLen = els.length;
	var pattern = new RegExp("(^|\\s)"+searchClass+"(\\s|$)");
	for (i = 0, j = 0; i < elsLen; i++) {
		if ( pattern.test(els[i].className) ) {
			classElements[j] = els[i];
			j++;
		}
	}
	return classElements;
}

function checkform(elemento)
{
	a = getElementsByClass('required',elemento,'*');
	for(i=0;i<a.length;i++)
	{
		
		if(a[i].value == "")
		{
			s = document.getElementById('submit');
			s.disabled = true;
			return false;
		}
	}
	s = document.getElementById('submit');
	s.disabled = false;
	return true;
}