In this example I will show you how easy it is to make such API calls in jQuery AJAX. It can be used to invoke (call) a method with an owner object as an argument (parameter). The task is to execute callbackFirst function first and then execute callbackSecond function. How to Call a Function Using jQuery. Syntax uery.fn.extend( There is a requirement to make multiple AJAXcalls parallellyto fetch the required data and each successive call depends on the data fetched in its prior call.