Javascript

reference: http://learnxinyminutes.com/docs/javascript/

A function is declared with the function() keyword

function doSomething(thing) {
    return console.log(thing.toUpperCase());
}
doSomething("lol");

Function objects don’t even have to be declared with a name – you can write an anonymous function definition directly into the arguments of another

setTimeout(function(){
    // this code will be called in 5 seconds' time
}, 5000);

jQuery event methods

reference: http://www.w3schools.com/jquery/jquery_events.asp

You must pass a function to the event

("p").click(function() {
   console.log("click!");
});

jQuery callback functions

reference: http://www.w3schools.com/jquery/jquery_callback.asp

A callback function is executed after the current effect is completed.

Typical syntax: $(selector).hide(speed,callback);

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

jQuery and AJAX

reference: http://www.jquery-tutorial.net/ajax/the-get-and-post-methods/

Typical syntax: $.get/post(URL, params, callback);

$.post("test_post.php",
{
    name: "John Doe",
    age: "42"
},
function(data, textStatus)
{
     alert("Response from server: " + data);
});

The first parameter of the callback function is the content of the page requested. Since most of times this content is json stuff, I could access its fields with data.name and alike.

The second parameter to the callback function is the request exit status.

If I use get instead of post, it would perform a GET request like test_get.php?name=John Doe&age=42