Complex sentence: Some browsers, notably Microsoft's Internet Explorer, will also display the alt attribute of an image as a tooltip in the same manner; if a title attribute is also specified, it will override the alt attribute for tooltip content.
Split into simpler sentences: Some browsers, notably Microsoft's Internet Explorer, will also display the alt attribute of an image as a tooltip in the same manner if an alt attribute is specified and a title attribute is not. If a title attribute is also specified, it will override the alt attribute for tooltip content.