ALT:
For user agents that cannot display images, forms, or applets, this attribute specifies alternate text.
TITLE:
This attribute offers advisory information about the element for which it is set.
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Values of the title attribute may be rendered by user agents in a variety of ways. For instance, visual browsers frequently display the title as a "tool tip" (a short message that appears when the pointing device pauses over an object). Audio user agents may speak the title information in a similar context. For example, setting the attribute on a link allows user agents (visual and non-visual) to tell users about the nature of the linked resource: