// 10px -> 10
function dimToInt(dim) {
	var l = dim.length;
	return parseInt(dim.substring(0,l-2), 0);
}

Event.observe(window, 'load', function() {
	if ( $('zona6') ) {
		var el = $('zona6');
		var mt = dimToInt(el.getStyle('margin-top'));
		var h = dimToInt(el.getStyle('height'));
		if ( $('zona4') ) {
			$('zona4').setStyle({
				marginTop: (mt+h)+'px'
			});
		}
	}
	
	if ( $('zona4') ) {
		el = $('zona4');
		mt = dimToInt(el.getStyle('margin-top'));
		h = dimToInt(el.getStyle('height'));
		//alert(mt+':'+h);
		if ( $('zona7') ) {
			$('zona7').setStyle({
				marginTop: (mt+h)+'px'
			});
		}
	}
	
	if ( $('zona8') ) {
		var h_s = 0;
		el = $('zona8');
		mt = dimToInt(el.getStyle('margin-top'));
		h = dimToInt(el.getStyle('height'));
		h_s += mt+h;
	}
	
	if ( $('zona7') ) {
		el = $('zona7');
		mt = dimToInt(el.getStyle('margin-top'))+dimToInt(el.getStyle('margin-bottom'));
		h = dimToInt(el.getStyle('height'));
		h_s += mt+h;
		//alert(h_s);
		$('zona10').setStyle({
			marginTop: h_s+'px'
		});
	}
});