var currentBlock =document.getElementById('sysreqs');

function hideCurrentBlock() {
	if (currentBlock != null) {
		currentBlock.style.display='none';
        currentBlock = null;
	}
}

function toggleBlock(elementId) {
	var el = document.getElementById(elementId);
	if (currentBlock == el) {
		if (el.style.display=='block') {
			el.style.display='none';
		} else {
			el.style.display='block';
		}
	} else {
		hideCurrentBlock();
		if (el) {
			el.style.display='block'
			currentBlock = el;
		}
	}
	return false;
  }