As we all know jQuery is a very small language. Not only is the file size of the jQuery library small, but the amount of code you need to write to achieve something is also very small. Because of this it is sometimes more efficient to write and test jQuery code in the browser than in a local file. To do this we need a couple of things.
- The Firebug Extension for Firefox
- Greasemonkey
If the page that we are going to manipulate doesn’t already include jQuery on it, then we can include it with this small Greasemonkey script. If jQuery is already included on the page, there is no use for this script.
// Add jQuery
var GM_JQ = document.createElement('script');
GM_JQ.src = 'http://jquery.com/src/jquery-latest.js';
GM_JQ.type = 'text/javascript';
document.getElementsByTagName('head')[0].appendChild(GM_JQ);
// Check if jQuery's loaded
function GM_wait() {
if(typeof unsafeWindow.jQuery == 'undefined') { window.setTimeout(GM_wait,100); }
else { $ = unsafeWindow.jQuery; letsJQuery(); }
}
GM_wait();
// All your GM code must be inside this function
function letsJQuery() {
alert($); // check if the dollar (jquery) function works
}
Source
With the jQuery library on the page we can now go ahead and start entering commands. For this example we’ll take jQuery.com, we can enter a basic jQuery Selector…
This is part 2 of a 2 part series on making a Todo List with PHP and enhancing it with jQuery’s AJAX
In part 1 of the tutorial, we covered the PHP and MySQL side of things. In this part we will be enhancing it with jQuery’s AJAX and manipulation functionality. The to-do list will degrade fine - if the user has Javascript disabled, the application will still work. All changes occur in the index.php file.
There are two parts to the script. One handles the posting of new posts, while the other handles posts being deleted. We’ll start with adding new posts.
//When the button with an id of submit is clicked (the submit button)
$("#submit").click(function(){
//Retrieve the contents of the textarea (the content)
var formvalue = $("#content").val();
//Build the URL that we will send
var url = 'submit=1&content=' + formvalue;
//Use jQuery's ajax function to send it
$.ajax({
type: "POST",
url: "process.php",
data: url,
success: function(){
//If successful , notify the user that it was added
$("ul").before("<p class='new'>You just added: <i>" + formvalue + "</i></p>");
}
});
//We return false so when the button is clicked, it doesn't follow the action
return false;
});
The url part confuses some people. What we are doing…
With the arrival of jQuery UI 1.5 i was browsing its’ wiki pages and learning all of the API. I came across the jQuery UI wiki page, its essentially more jQuery effects except these ones are alot more dynamic! You can explode, puff, slide, highlight and alot more. I was a amazed that i hadn’t seen this page or been linked to it before, its something the jQuery UI team should be proud of.
Check it out
For those of you with no jQuery background what-so-ever, jQuery UI is a series of user interface (UI) enhancements made in Javascript. These range from tabs (which also support ajax loading), to dialog boxes which you can drag, drop and resize. All cross browser! Although its currently still under development the finish line is in sight for the 1.5 release. I encourage everyone to check it out, it can add some really professional effects to your website for minimal lines of code.
“Whats a good jQuery menu?” is a question I hear quite frequently on blogs and forums. As jQuery is such a simple language to learn, most people code their own for their own sites. I’ve compiled a list of 3 menu plugins, and and 5 ‘custom’ solutions that people have setup.
http://p.sohei.org/jquery-plugins/menu/
Latest release: Jan 07
This plugin was constructed to emulate a desk top apps menu. They don’t close until clicked off and are activated by clicking them (rather than hovering). It requires the jQuery dimensions plugin to perform ‘smart calculations’.
Example Usage: http://p.sohei.org/stuff/jquery/menu/demo/demo.html
Download: http://p.sohei.org/jquery-plugins/menu/
http://jdsharp.us/jQuery/plugins/jdMenu/
Latest release: April 08
Although the jdMenu plugin is only 3kb itself, it depends on or looks a hell of a lot better with the plugins dimension, positionBy and bgiframe. jdMenu boasts keyboard access and can be easily made into a verticle menu by changing an option.
Example Usage & Download: http://jdsharp.us/jQuery/plugins/jdMenu/
http://users.tpg.com.au/j_birch/plugins/superfish/
Latest release: Sometime in 08
Superfish takes a CSS based dropdown then enhances it with jQuery so if the user has Javascript disabled, it degrades perfectly well. Since the menu is mainly CSS based, I’d imagine it’s a fair bit faster than the other options.
Example Usage: http://users.tpg.com.au/j_birch/plugins/superfish/#examples
Download: http://users.tpg.com.au/j_birch/plugins/superfish/#download
More menus
Plugins are useful, but a lot of the time you don’t need their…
We all know that jQuery is great, that you can do things in 2-3 lines in jQuery that you can in 20 lines of Javascript, but is your jQuery code starting to get a bit bulky? Could you do things better?. I’m going to show you how to reduce a 20-25 line jQuery script into 3 lines by making the script dynamic, and give a few tips on improvement of your code.
What we want: When the user clicks a list item, it will show the corresponding div
http://www.php.net
http://www.asp.net
http://www.ruby-lang.org
http://www.python.org
http://www.adobe.com/products/air/
If i were a beginner and i was asked to write the script, i’d most likely code sections for each id/div such as below.. Once the specified link is clicked it’ll hide all the divs shown(the other content panels) and then it’ll fade in the relevant content panel.
$("ul#langs li#php").click(function(){
$("div#container div").hide();
$("div#container div#d_php").fadeIn("slow");
});
$("ul#langs li#asp").click(function(){
$("div#container div").hide();
$("div#container div#d_asp").fadeIn("slow");
});
This is alright.. it does the job but for each id/div you need around 3 lines of code, your also listening for alot of events (all of those clicks) which may use more memory and slow the script down in general.
Instead of listening for unique clicks(php, asp, ruby etc..), why don’t we just listen for…
Woo! Another screencast. In this one i show you how to include your twitter stream into your blog or website, and then format it using jQuery so your tweets have an alternating background colour.
The jQuery team are approaching the UI 1.5 release, the library of demos is steadily building up and i personally cannot wait until its fully released 
. One of the “weaker” points of other Javascript User Interfaces and previous releases were the themes for the window borders etc. This has been solved in jQuery UI 1.5 with the theme roller. Its a well polished theme roller with features like the jQuery colour picker in it, you set the necessary classes and you can see a live demo of what it will look like on dialogs, sliders and tabs below, very nice.
Heres a video by the Filament group, who made the theme roller.
ThemeRoller for jQuery UI Screencast v4 from filamentgroup on Vimeo.
Heres Part 2 of the jQuery AJAX login tutorial. If you haven’t already, i suggest you read part 1 located here.
We are going to start writing the PHP code to process the form. This is fairly basic stuff, using $_POST to get the values from the form, then checking them against pre-assigned values, if they match, then echo approved, if they don’t then echo denied.
So at the end of this stage, you will have an HTML form set up and this PHP file. You can enter the username Panzer and the password of query7 into the form and it will return Logged in.
Next tutorial, the fun part, the AJAX!
Heyo. This is going to be the first of 4 tutorials on making a jQuery powered AJAX login system with a PHP backend. The series of tutorials will go like so.
- Plan, code the form (This tutorial)
- Code the PHP backend, make it work
- Code the AJAX, implement it.
- Tidy it up, make it look snazzy
Ok then. So we will have a forum with 2 inputs; username and password. The user will enter the details and we’ll use PHP to authenticate them. If its true, we can set a cookie or echo some text. We will then implement jQuery’s AJAX and make the whole thing seemless. Some nice little fades will be added at the end.
So, the form. Its a plain and simple HTML form. Nothing special about it.
Thats all for now. Next lesson we will code the PHP and “make it work“.
