asking about basic javascript line by line

Question

As I understand JS code is executed line by line. Why then in the code below alert is performed before hide?

$(document).ready(function(){
    $("button").click(function(){
         $("p").hide();
        alert("The paragraph is now hidden"); 
    });
});

Answer 1

That is because the DOM manipulations are usually a bit heavy and are rendered after all the statements in the mentioned event loop are executed.

As @Pointy rightly mentioned, the layout is rendered only after the registered statements are executed.