DataSet Property are Case-Insensitive
HTML is case-insensitive, but often forgotten that dataset property name either. such as:
<div data-foobar data-fooBar data-foo-bar><div>
data-foobar data-fooBar are the same thing, map to dom dataset API of .dataset.foobar property.
To create a camel case dataset property, use dash separated, such as foo-bar as `dataset.fooBar.
If double dash foo--bar used, map to dataset['foo-Bar'].
