Response.js (ResponseJS.com) uses [0, 320, 481, 641, 961, 1025, 1281] as default breakpoint mins, and it uses these to create two sets of data attributes. One is for changing the src attribute, and the other is for changing entire blocks of markup: - default *src* attributes: data-src0, data-src320, ... data-src1281 - default *markup* attributes: data-r0, data-r320, ... data-r1281 It is possible (and easy) for devs to customize the breakpoints, prefixes, mode, etc. using the Response.create() method. USAGE EXAMPLES