11
Fri, Oct
6 New Articles

TechTip: jQuery Fundamentals, Part II

Web Languages
Typography
  • Smaller Small Medium Big Bigger
  • Default Helvetica Segoe Georgia Times

When ready, please slide me in.

 

In Part I, I wrote about how to retrieve the content of input fields, changing many elements on a Web page by using id, or class selectors. Now, I'll introduce you to the .ready() function and some of the animation functions found in the standard jQuery library.

 

So if you want to see something very useful and also pretty cool, please have a seat in the jQuery boat and we'll set sail on the next line.

jQuery .ready() Function

The execution of JavaScript/jQuery statements is done line by line, or asynchronously, or when it is ready for the browser to execute it. This means that if you place JavaScript code above code that refers to an element at the bottom of your page, you'll get an error. To prevent this scenario, you can use the .ready function, which will guarantee that the code is not executed before the DOM is ready. In plain English, if you want to do something to an object on your page and you want to be sure that the page is fully loaded, you should place your code inside the .ready function.

 

101912Janfigure1v2  
Figure 1: Adding the CSS makes the difference in the header description.

 

For a live example, click the links below to see the difference when executed in a browser.

 

Not using .ready()

http://agnethe.dk/mcpressonline/jquery_fundamentals_part2/ex1.htm

 

Using .ready()

http://agnethe.dk/mcpressonline/jquery_fundamentals_part2/ex2.htm

 

Here, you see the .ready function in action, and you can view the source. At the end of this TechTip, you can download the examples.

jQuery Animations

Sometimes, you need to show or hide elements on a Web site or you need to fade out something when an action happens to an element. To do that using "normal" JavaScript can be a daunting task, but when using jQuery, it often can be done with a few lines of code.

 

Below are some examples showing how the .hide(), .show(), and .slideToggle() functions work. I have deliberately not included the .animate() function simply because I consider it a little over the top for this tip, but if you want to see it in action, click here.

 

jQuery has a lot of other animation functions, so try digging into it on the jQuery Web site. If the standard animations in jQuery are not enough, turn your eyes to the jQuery UI extension, which offers a wide selection of animations and a lot of other cool stuff.

 

Because this is a first glance, I won't use jQuery UI in this tip, but I will come back to it sometime next year and show you an introduction. If you cannot wait, point your browser to http://jqueryui.com/ and discover it for yourself.

 

Now, let's move on to see some useful animations at work.

 

.hide() will hide the matched elements. The elements can be hidden by using the slow/fast constants or by using a duration time, which is specified in milliseconds. You can, as always, use the jQuery selectors to hide things such as an HTML tag, an id, or a class.

 

.show() will, as you might have guessed, show the matched elements. It works under the same rules as the .hide() function.

 

Click here to see some examples of using the .hide() and .show() functions.

 

.slideToggle() allows you to you can display or hide, with a sliding motion, the matched elements.

 

Now you know the main rules, so I will not repeat myself about the selector thing.

 

Instead, let's look at an example I created; it's a Web page with music questions for you to answer. If you need help, you can click the Help link and some help text will be revealed before your very eyes. By clicking Help again, the text will vanish.

 

101912Janfigure2      
Figure 2: Let's quiz while testing the jQuery .slideToggle() function.     

 

Click here to see this example of using the .hide() and .show() functions.

 

To download all the examples click here.

Summary

This was the second TechTip in my jQuery fundamentals series, and once again I hope it will make you say, "Hmm, maybe he's getting somewhere...."

 

In the next tip, I'll talk about "callback" functions and how they can help you in your programming life.

 

Till' next time, take a break from programming once in a while and listen to some good music.

Jan Jorgensen

Jan Jorgensen is one of the owners of www.reeft.dk, which specializes in mobile and i5 solutions. He works with RPG, HTML, JavaScript, Perl, and PHP. You can reach him at This email address is being protected from spambots. You need JavaScript enabled to view it.

 

BLOG COMMENTS POWERED BY DISQUS

LATEST COMMENTS

Support MC Press Online

$

Book Reviews

Resource Center

  • SB Profound WC 5536 Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application. You can find Part 1 here. In Part 2 of our free Node.js Webinar Series, Brian May teaches you the different tooling options available for writing code, debugging, and using Git for version control. Brian will briefly discuss the different tools available, and demonstrate his preferred setup for Node development on IBM i or any platform. Attend this webinar to learn:

  • SB Profound WP 5539More than ever, there is a demand for IT to deliver innovation. Your IBM i has been an essential part of your business operations for years. However, your organization may struggle to maintain the current system and implement new projects. The thousands of customers we've worked with and surveyed state that expectations regarding the digital footprint and vision of the company are not aligned with the current IT environment.

  • SB HelpSystems ROBOT Generic IBM announced the E1080 servers using the latest Power10 processor in September 2021. The most powerful processor from IBM to date, Power10 is designed to handle the demands of doing business in today’s high-tech atmosphere, including running cloud applications, supporting big data, and managing AI workloads. But what does Power10 mean for your data center? In this recorded webinar, IBMers Dan Sundt and Dylan Boday join IBM Power Champion Tom Huntington for a discussion on why Power10 technology is the right strategic investment if you run IBM i, AIX, or Linux. In this action-packed hour, Tom will share trends from the IBM i and AIX user communities while Dan and Dylan dive into the tech specs for key hardware, including:

  • Magic MarkTRY the one package that solves all your document design and printing challenges on all your platforms. Produce bar code labels, electronic forms, ad hoc reports, and RFID tags – without programming! MarkMagic is the only document design and print solution that combines report writing, WYSIWYG label and forms design, and conditional printing in one integrated product. Make sure your data survives when catastrophe hits. Request your trial now!  Request Now.

  • SB HelpSystems ROBOT GenericForms of ransomware has been around for over 30 years, and with more and more organizations suffering attacks each year, it continues to endure. What has made ransomware such a durable threat and what is the best way to combat it? In order to prevent ransomware, organizations must first understand how it works.

  • SB HelpSystems ROBOT GenericIT security is a top priority for businesses around the world, but most IBM i pros don’t know where to begin—and most cybersecurity experts don’t know IBM i. In this session, Robin Tatam explores the business impact of lax IBM i security, the top vulnerabilities putting IBM i at risk, and the steps you can take to protect your organization. If you’re looking to avoid unexpected downtime or corrupted data, you don’t want to miss this session.

  • SB HelpSystems ROBOT GenericCan you trust all of your users all of the time? A typical end user receives 16 malicious emails each month, but only 17 percent of these phishing campaigns are reported to IT. Once an attack is underway, most organizations won’t discover the breach until six months later. A staggering amount of damage can occur in that time. Despite these risks, 93 percent of organizations are leaving their IBM i systems vulnerable to cybercrime. In this on-demand webinar, IBM i security experts Robin Tatam and Sandi Moore will reveal:

  • FORTRA Disaster protection is vital to every business. Yet, it often consists of patched together procedures that are prone to error. From automatic backups to data encryption to media management, Robot automates the routine (yet often complex) tasks of iSeries backup and recovery, saving you time and money and making the process safer and more reliable. Automate your backups with the Robot Backup and Recovery Solution. Key features include:

  • FORTRAManaging messages on your IBM i can be more than a full-time job if you have to do it manually. Messages need a response and resources must be monitored—often over multiple systems and across platforms. How can you be sure you won’t miss important system events? Automate your message center with the Robot Message Management Solution. Key features include:

  • FORTRAThe thought of printing, distributing, and storing iSeries reports manually may reduce you to tears. Paper and labor costs associated with report generation can spiral out of control. Mountains of paper threaten to swamp your files. Robot automates report bursting, distribution, bundling, and archiving, and offers secure, selective online report viewing. Manage your reports with the Robot Report Management Solution. Key features include:

  • FORTRAFor over 30 years, Robot has been a leader in systems management for IBM i. With batch job creation and scheduling at its core, the Robot Job Scheduling Solution reduces the opportunity for human error and helps you maintain service levels, automating even the biggest, most complex runbooks. Manage your job schedule with the Robot Job Scheduling Solution. Key features include:

  • LANSA Business users want new applications now. Market and regulatory pressures require faster application updates and delivery into production. Your IBM i developers may be approaching retirement, and you see no sure way to fill their positions with experienced developers. In addition, you may be caught between maintaining your existing applications and the uncertainty of moving to something new.

  • LANSAWhen it comes to creating your business applications, there are hundreds of coding platforms and programming languages to choose from. These options range from very complex traditional programming languages to Low-Code platforms where sometimes no traditional coding experience is needed. Download our whitepaper, The Power of Writing Code in a Low-Code Solution, and:

  • LANSASupply Chain is becoming increasingly complex and unpredictable. From raw materials for manufacturing to food supply chains, the journey from source to production to delivery to consumers is marred with inefficiencies, manual processes, shortages, recalls, counterfeits, and scandals. In this webinar, we discuss how:

  • The MC Resource Centers bring you the widest selection of white papers, trial software, and on-demand webcasts for you to choose from. >> Review the list of White Papers, Trial Software or On-Demand Webcast at the MC Press Resource Center. >> Add the items to yru Cart and complet he checkout process and submit

  • Profound Logic Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application.

  • SB Profound WC 5536Join us for this hour-long webcast that will explore:

  • Fortra IT managers hoping to find new IBM i talent are discovering that the pool of experienced RPG programmers and operators or administrators with intimate knowledge of the operating system and the applications that run on it is small. This begs the question: How will you manage the platform that supports such a big part of your business? This guide offers strategies and software suggestions to help you plan IT staffing and resources and smooth the transition after your AS/400 talent retires. Read on to learn: