Ajax
jQuery provides convenience methods that make Ajax calls easier. jQuery exposes an
ajax
method that allows sophisticated control over an Ajax call. It also provides con‐
venience methods,
get
and
post
, that perform the most common types of Ajax calls.
While these methods support callbacks, they also return promises, which is the rec‐
ommended way to handle the server response. For example, we can use
get
to rewrite
our
refreshServerInfo
example from before:
function
refreshServerInfo
() {
const
$serverInfo
=
$
(
'.serverInfo'
);
$
.
get
(
'http://localhost:7070'
).
then
(
// successful return
function
(
data
) {
Object
.
keys
(
data
).
forEach
(
p
=>
{
$(
`[data-replace="
${
p
}
"]`
).
text
(
data
[
p
]);
});
},
function
(
jqXHR
,
textStatus
,
err
) {
console
.
error
(
err
);
$serverInfo
.
addClass
(
'error'
)
.
html
(
'Error connecting to server.'
);
}
);
}
As you can see, we have significantly simplified our Ajax code by using jQuery.
Conclusion
The future of jQuery is unclear. Will improvements to JavaScript and browser APIs
render jQuery obsolete? Will the “vanilla JavaScript” purists be vindicated? Only time
will tell. I feel that jQuery remains useful and relevant, and will so for the foreseeable
future. Certainly the usage of jQuery remains quite high, and any aspiring developer
would do well to at least understand the basics.
If you want to learn more about jQuery, I recommend
Earle Castledine and Craig Sharkie. The online
good.
280 | Chapter 19: jQuery
