These are chat archives for canjs/canjs
Not possible in most cases
Each ajax call involves the browser sending information to a server at a particular URL.
If you reduced the browser code from two ajax calls to one ajax call, the server would receive less information, the browser would not receive some information it is getting now, and/or the server would perform fewer operations.
If you control the server code, you might be able to change the server code to be able to do both operations in one step. Only then could you change the browser code.