var state = 0;

function selectAll(formName){

	var cbTotal = document[formName].elements.length;
	
	for (var i=0;i<cbTotal;i++) {
		if (state == 0){
			selectElement(document[formName].elements[i], true);
		}
		else{
			selectElement(document[formName].elements[i], false);
		}
	}

	if (state == 0){
		state = 1;
		document.getElementById('A').style.display="none";
		document.getElementById('B').style.display="block";
	}
	else{
		state = 0;
		document.getElementById('A').style.display="block";
		document.getElementById('B').style.display="none";
	}
}

function selectElement(element, value) {
	if (element.disabled != true) {
		element.checked = value;
	}
}