hide - Understanding jQuery

What’s important is the return value. The example above ignores the return value completely.
Luckily, jQuery allows us to capture it. In order for us to see this in action, we need to use a
slightly different syntax shown below:
$.ajax( { url: “script.php”,
type: “post”,
success: function(result) { alert(result); }
});
Still the same function. The only difference is that now we are using JSON with objects inside:
url, type and success. JSON is discussed earlier in this book.
Note that the “result” parameter passed to the success function is the data received from the
script. You are the one to decide what that returned data should be within your “script.php”
file. Again, it can be XML, plain text or any other kind of data, depending on the purpose of
your asynchronous HTTP request. You can format the function above in any way you wish,
but the point is that you specify either the POST or GET type using the “type” parameter.
Remember that everything in Javascript is an object? This is what makes it possible to assign a
function closure to the success parameter in the example above. Even “script.php” and “post”
values are actually objects of type String.
What are some of the things that Ajax can be used for?
Forms: jQuery Ajax is incredibly helpful when dealing with HTML web forms. Using selectors
it is possible to collect and send all values from all fields of the form directly to your form
processing script without having to retype the id’s, names or values from the form elements.
Let’s take a look at how you can use jQuery selectors along with Ajax to submit information
from an arbitrary form. Let’s say we have a form like this:
Note that there is no need to use the form tag at all unless you think you must. We’re avoiding
the regular HTML form submit and overriding it with the way we want it to work.
38