(For more resources on WordPress and jQuery, see here.)
The following are the tips and tricks required for working with jQuery and WordPress.
Keep a code arsenal
A “snippet collection” or, what I call my “code arsenal” will go a long way to help you out, not just with jQuery and WordPress code, but also with the general HTML markup and even CSS solutions you create, not to mention any other code language you work in.
I’m terrible at remembering syntax for code, markup, and CSS. I often know what I need, but can never quite recall exactly how it’s supposed to be typed. I used to spend hours going through various stylesheets, markup, and codes from previous projects to copy into my current project as well as googling (and “re-googling”) web pages that had samples of the syntax I needed.
If you often find yourself in a similar situation, using the Snippets or Clip features that are usually available in good HTML/Code editors will free you from this mundane (and very time consuming) task. You simply type or paste the WordPress template tags, functions, PHP code, key CSS rules, and jQuery functions (and any other code syntax, whatever you find you need to use the most), into the Snippets or Clips panel available in your editor, and the application saves it for you, for future use.
As you work on different projects, you’ll come up with solutions that you’ll probably want to use again in the future, say, a set of CSS rules for unordered lists that make a nice gallery view, or a very clever use of two jQuery functions together. Every time you create something you think may come in handy (and a lot of it will come in handy again), be sure to save it right then and there, for future reference.
Good editors such as Dreamweaver, HTML-Kit, and Coda usually have the ability to organize snippets and keep them logically grouped so they’re easy to access. Some editors will even let you assign custom “key shortcuts” and/or drag-and-drop to your clips right into your working file. How easy is that?
Free your arsenal
Once you discover how handy this is, you might want to have your arsenal available to other programs you work with, especially if you switch between multiple editors and authoring environments. I suggest you invest in a multi- paste/clip board application that lets you save and organize your code snippets. When I was on a PC, I used a great little app called Yankee Clipper 3 (which is free and is available at http://www.intelexual.com/products/YC3/), and now on the Mac, I use iPaste (which has a modest price; go to http://www.iggsoftware.com/ipaste/). In addition to having your arsenal handy from any application, being able to go back through the last 10 or so items you copied to the clip board is a real time saver when you’re working on a project.
Your arsenal on-the-go
Last, I find I like to take most of my arsenal with me. If you use a handheld device or have a phone with a note app that lets you categorize and search for notes (especially the one that will let you sync from your desktop or a web service), you’ll probably find it useful to keep some or all of your arsenal in it so you can easily look up syntax from your arsenal at any time. I occasionally freelance at places that require me to use one of their computers and not my laptop, so having access to my arsenal on my device is very useful.
Palm’s native note app suited me great in this capacity for years and years; I now keep a large part of my arsenal in Google docs and use a little desktop app called NoteSync, which lets you write and view Google docs notes quickly (they’ll have an Android app out soon, but in the meantime I use Gdocs on my Android device to see my notes). I have many friends who swear by EverNote’s system (though, their mobile app only works offline on the iPhone and not on Android—as of yet).
Once all your often used and creative one-off solutions are all located in a convenient (hopefully categorized and key-word-searchable) place, you’ll be amazed at the amount of speed your development picks up and how much more relaxing it is.
jQuery tips and tricks for working in WordPress
Let’s start-off with some of my favorite jQuery tips and tricks, before focusing on WordPress.There are also a few nuggets that will help you speed up your jQuery development.
Try to use the latest version of jQuery
This is one of the drawbacks to using the bundled WordPress version: it may get a little behind the current version of jQuery until the next version of WordPress comes out. I’m all for staying on top of the current version as jQuery’s top goals for version releases are not just to provide new functionality, but continually streamline and improve the performance and speed of the existing functionality. If the latest version of jQuery available on CDN is greater than the version that’s bundled, be sure to deregister jQuery first or restrict your newer version with the if else statements, so it loads on the front end of the site on required pages only. Otherwise, you may create problems with plugins using the bundled version of WordPress.
Stay current with the Google CDN
Stay in No Conflict mode
The great thing about WordPress is that a site can have so many people contributing to it in lots of different ways: writing content, working on the theme, and adding WordPress plugins. One of the worst things about WordPress is that so many people can easily contribute who knows what to a site, depending on their admin status, some other collaborator could add to them, or what plugins they could install.
Staying in No Conflict mode is a must for WordPress. This in conjunction with using the wp_enque_script to load in WordPress will ensure that jQuery doesn’t get “pushed out” if anyone loads up any other plugin that uses say MooTools or Scriptaculous, or even just an older version of jQuery.
It’s easy to stay in noConflict mode. Just use jQuery instead of the shortcut dollar sign ($) in front of your scripts.
Make sure other scripts in the theme or plugin use the Script API
If you’re using a theme or a plugin from a third party, take a look through the theme’s header.php file or the plugin’s PHP pages and double-check that all scripts have been loaded in using the register and wp_enqueu_script methods. I’ve had a few instances that were rather frustrating and caused some hair-pulling, as we tried to figure out why my jQuery scripts were not working or wondering how I “broke” them porting them over to the live site. Turns out, the live site had a plugin installed that my sandbox site didn’t, and you guessed it, that plugin was including an older version of jQuery and a custom script file using hard-coded script tags instead of the wp_enqueue_script method. Once this was figured out and straightened up, setting everything into noConflict mode, everything worked fine again!
Check your jQuery syntax
This one always gets me. You write up a nifty little jQuery chain, add a few tweaks to it, and the darn thing just stops working. And you know it’s right! Well, at least, you think it’s right. Right? This is where a great code editor comes in handy. You’ll want some nice find features that let you step through and look at each returned find, as well as let you run a find not just on the whole document, but on individual selections. I like to select the just the “offending chain” and run the following find features on it to see what comes up.
Colons and semicolons
Do a find for : (colons); you’ll probably find a few that are accidentally set up as ; (semicolons) in your function’s various object parameters, or you may have typed a colon where a semicolon should have been there.
I’ll also run a find on closing parenthesis, ), and make sure each one that comes up is part of a continuing chain or the end of the chain marked with a;.
Mismatched double and single quotes
Last, a quick check for matched-up single and double quotes sometimes shows me where I’ve messed up. Panic’s Coda lets you place in “wild cards” into the find so a search for “*’ or ‘*” usually turns up a pesky problem.
Most good code editors have color-coded syntax, which really helps in recognizing when something isn’t right with your syntax, such as not having a closing quote mark at all or parenthesis. But, the issues above are tricky as they’ll still often display as proper color coded syntax, so you don’t know until you run your script that something’s wrong.
Use Firefox and Firebug to help with debugging
First up, there’s the console.log and console.info statements which you can add to your jQuery scripts to pass info to and have a plethora of useful (and sometimes not-so-useful, but interesting) information about your script returned.
console.profile and console.time are great for measuring how fast you scripts are being processed by the browser.
For a complete overview of everything Firebug’s console can do, check out: http://www.getfirebug.com/logging.