Input Hints 介绍
Uses the title attribute of the input element to hint as to what the input
field is for.
When the element is in focus, it’s removed. If it’s left blank it will place
the hint back in.
Also applies a ‘blurred’ class via the only parameter, otherwise defaulting to
‘blur’.
Finally, it will remove the text if the form is submitted and has been left
blank.
Note that this plugin also gets around the autocomplete feature in Firefox.