[bes]

вот так без дополнительного клика

<div id="div" style="position: fixed; top: 10px; left: 5px; z-index: 100">
	<a href="#" onclick="return false">open</a>
	<div style="display: none">
		<input><br>
		<input>
	</div>
</div>
<div></div>

<br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
<br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
<input onclick="alert('input')">

<script>
window.onload = function () {
	var div = document.getElementById('div');
	
	div.onclick = function (e)  {
		e = e || event;
		var target = e.target || e.srcElement;
		if (target == this.children[0]) {
			var next = target.nextSibling.nextSibling; 
			if (next.style.display != 'block') {
				next.style.display = 'block';
				target.innerHTML = 'close';
				div.nextSibling.nextSibling.style.cssText = 'position: fixed; left: 0px; top: 0px; height: 100%; width: 100%; z-index: 99';
			} else {
				next.style.display = 'none';
				target.innerHTML = 'open';
				div.nextSibling.nextSibling.style.cssText = '';
			}
		}
	}
	
	div.nextSibling.nextSibling.onclick = function (e) {
		e = e || event;
		div.children[1].style.display = 'none';
		div.children[0].innerHTML = 'open';
		this.style.cssText = '';
		var elem = document.elementFromPoint(e.clientX, e.clientY);
		elem.focus();
		elem.click();
	}
	
}
</script>