Regarding inputs and spans being inline elements, there is no need to float them.
<input type="text" size="3" name="ip0" class"ipAddress">
<span class"ipAddress">.</span>
<input type="text" size="3" name="ip1" class"ipAddress">
<span class"ipAddress">.</span>
<input type="text" size="3" name="ip2" class"ipAddress">
<span class"ipAddress">.</span>
<input type="text" size="3" name="ip3" class"ipAddress">
<span class"ipAddress">.</span>
To align elements vertically, utilize CSS position: relative;
and top:
.
From a user perspective, having four separate input boxes for an IP address may not be user-friendly. It can make typing difficult and copying/pasting becomes challenging.
From an application standpoint, having separate input boxes doesn't offer much benefit.
In my opinion, it would be better to abandon the idea and opt for a single input field instead.