Working with Ajax normally require the server to answer one of the following types:

1. XML data
2. JSON data
3. HTML code
4. Textual data

Tequila provide access to all of them,

Serverblocks

Not an ajax method but a way to integrate multiple screens into one on the server side, in this case PHP calls an MVC (dispatcher) class and request a new method, parameters can be passed using the task definition but the class should be coded to read them. 

See mashups for more info

Blocks

It is possible to have a block of code returning alternatively a complete page or a clean block to be loaded inside a DIV or any other control.

The default mode for any call is page, to display only the HTML code of the block and no HTML headers or CSS/JS includes call 

rrt=bl or block

Blocks and JS/CSS

Taking advantage of the caching capabilities of Tequila and to avoid errors on browsers, all JS/CSS includes are removed when calling rrt=block

XML

Check XML section to learn more about

Libraries

For client side you can use any library you like, Tequila ships with it's own Ajax library to simplify things but you can replace for any you like.