How to Check if a jQuery Function is Defined

You can use the 'typeof' operator to check if a jQuery function is defined. For example:

if (typeof jQuery.fn.myFunction === 'function') {
  // myFunction is defined
} else {
  // myFunction is not defined
}

In this example, 'jQuery.fn.myFunction' is the function you want to check if it is defined. The 'typeof' operator will return 'function' if the function is defined, and 'undefined' if it is not defined.