TypeError $.ajax is not a function

In web Development using jquery for front-end development encountered such a problem, tangled up for a long time finally solved, the following is the solution.

You can refer to the following several methods of troubleshooting.

1. First check whether the library of jquery is referenced.

2. Page if you are using an IFRAME nested pages check whether the upper page also references the JQuery class library and the underlying page resulting in a duplicate reference.

3. If other JS frames are referenced and jquery conflicts are created, try replacing the "$" symbol with "jquery" if you have one.

TypeError $.ajax is not a function