Application and difference between conpile and link in angular JS

The link method is a way for compile to throw out

Application

App.directive ("ThumbNail", function () {
    return{
        Restrict: "ACE",
        Replace:true,
        Templateurl: ". /tpl/tpl.html ",
        Compile:function (elem,attrs,transclude) {
            Dom Dom tree additions and deletions (at this point the DOM tree has not yet formed)
            Console.log ("compile phase"); Print only once only once
            return{
                Pre:function (Scope,elem,attrs,controller) {

            Equivalent to the  Post-link method

          
                    Console.log ("compile Phase 1")

                },
                Post:function (Scope,elem,attrs,controller) {//equals Post-link method
                    Console.log ("link Stage")//Bind event with data (DOM tree formed)  Each instance is executed once
                }

            }
        }
        /*link:function (scope,elem,attrs) {
            Console.log (Elem);
            Angular.element (Elem). Find ("a"). EQ (0). On ("click", Function () {
                Alert ("Add to Favorites")
            });
            Angular.element (Elem). Find ("a"). EQ (1). On ("click", Function () {
                Alert ("Click to buy")
            })
        }*/
    }
});

Application and difference between conpile and link in angular JS