jQuery - Write data-* attribute and get it

data-attibute.js

/**
 * Write data-* attribute and get it.
 * 
 * When you make a call to .data, jQuery looks for any data-* attributes, and adds it to the data collection.
 * However, THIS ONLY HAPPENS ONCE. Subsequent calls to .data will not look at the element's data-* attributes.
 * 
 * Source: http://stackoverflow.com/questions/12271362/writing-to-a-data-attribute-and-getting-it-with-jquery-data/12271393#12271393
 * Related and very important: http://stackoverflow.com/questions/7261619/jquery-data-vs-attr#7262427
 */
$('.foo').attr('data-bar', 'baz');

var dataBar  = $('.foo').attr('data-bar');