Jackpot Numbers - JavaScript Just For Fun

Sometimes when updating an HTML value using JavaScript it is appropriate to animate the HTML in some that draws the users eye to the change. Often designers choose to animate the opacity or a background color. Today’s widget illustrates a different approach to use with numbers, where the value quickly counts up or down from the current value to the correct value.


Sampled by © JavaScriptBank.com

Sometimes when updating an HTML value using JavaScript it is appropriate to animate the HTML in some that draws the users eye to the change. Often designers choose to animate the opacity or a background color. Today's widget illustrates a different approach to use with numbers, where the value quickly counts up or down from the current value to the correct value.

Example 1: Jackpot Numbers

(function() { var Y = YAHOO, YD = Y.util.Dom, YL = Y.lang, _addNumbers = function(n) { var result = 1, i = 2; for (; i &lgt; = n; i += 1) { result += i; } return result; }, _handleAnimation = function() { var _this = this; // improves compression _this.value += Math.round(_this.stepSize * _this.stepCount); _this.node.innerHTML = _this.formatFx(_this.value); _this.stepCount += 1; if (_this.stepCount >= _this.animSteps) { _this.timeout.cancel(); _this.node.innerHTML = _this.formatFx(_this.finalValue); } }; Core.Widget.JackpotNumbers = { incrementTo: function(elem, endPoint, conf) { var node = YD.get(elem), cfg = YL.isObject(conf) ? conf : {}, currValue, isIncrement, diffValue; if (! node) { Y.log('Invalid node passed to Core.Widget.JackpotNumbers.incrementTo'); return; } currValue = parseInt(node.innerHTML.replace(/[^0-9\.]/, ''), 10); if (isNaN(currValue)) { Y.log('Node did not resolve to number in Core.Widget.JackpotNumbers.incrementTo'); return; } isIncrement = currValue < endPoint; diffValue = isIncrement ? endPoint - currValue : currValue - endPoint; if (! YL.isNumber(cfg.animLength)) {cfg.animLength = 1000;} if (! YL.isNumber(cfg.animSteps)) {cfg.animSteps = 20;} if (! YL.isFunction(cfg.formatFx)) {cfg.formatFx = function(n) {return n;};} cfg.multiplier = _addNumbers(cfg.animSteps); cfg.animFreq = cfg.animLength / cfg.animSteps; cfg.stepCount = 1; cfg.stepSize = (isIncrement ? 1 : -1) * diffValue / (cfg.multiplier); cfg.node = node; cfg.value = currValue; cfg.finalValue = endPoint; cfg.timeout = YL.later(cfg.animFreq, cfg, _handleAnimation, null, true); } }; }());

The animation is setup in the static 'incrementTo' function, while the actual DOM animation occurs in the private '_handleAnimation' function. Call the 'incrementTo' function to begin animating a number in the DOM. It requires two parameters ('elem' - a string ID or DOM pointer, and 'endPoint' the number to animate to) and one optional parameter ('conf' - a configuration object). The function then calculates if the 'endPoint' is greater than or less than the current value in the provided DOM element to determine whether it should add or subtract. It then calculate an arithmetic multiplier using an additive method (if 'animSteps' is 5, then the multiplier is 1 + 2 + 3 + 4 + 5 = 15), based on the number of animation steps, so that the rate of addition will increase as the number nears the 'endPoint'. This multiplier is used to calculate the step size. All values are stored on a configuration object which is passed into an interval timer, with the period determined by the length of animation divided ("cfg.animLength") by the number of animation steps ("cfg.animSteps").

The configuration parameter has properties that can be controlled by the developers: 'animLength', 'animSteps', and 'formatFx'. The animation length is the number of milliseconds it should take for the animation to reach the 'endPoint'. The animation steps is the number of additive steps to take to reach the 'endPoint'. And the 'formatFx' is a function that should take a number as its first parameter and return a string, presumably the number in a desired format. These 3 configuration properties give the developer control over most of the animation attributes.

The '_handleAnimation' function simply adds the the value of the 'stepCount' multiplied by the 'stepSize' (so each addition is slightly larger than the previous) and updates the DOM node. Once the 'stepCount' equals the total number of animation steps ('animSteps'), then the interval timer is stopped and the DOM node is updated with the 'endPoint' value to correct any rounding issues.

Although, I probably won't use this widget very often, it is a lot of fun to play with. Here is a Demo Page to give it a try.

Limitations

The function will remove all number numeric characters from the node, so only use this on DOM nodes containing numbers. It also currently parses to integer, so any decimal places will be lost.

Language
Translate this page to English Translate this page to French Translate this page to Vietnamese

Recent articles
Migrate to Angular: why and how you should do it
The Possible Working Methods of Python Ideology
JavaScript Research Paper: 6 Writing Tips to Craft a Masterpiece
Learning How to Make Use of New Marketing Trends
5 Important Elements of an E-commerce Website
How To Create A Successful Prototype For Your PCB
WordPress Landing Page Conversion Essentials to Convert More
4 Development Hacks To Make Your Website Launch A Success
Why Data Recovery Software and Services are Important
Why Engineers Specializing in DevOps Are the Wave of the Future


Top view articles
Top 10 Beautiful Christmas Countdown Timers
65 Free JavaScript Photo Gallery Solutions
Best Free Linux Web Programming Editors
Top 50 Most Addictive and Popular Facebook mini games
Top 10 Free Web Chat box Plug-ins and Add-ons
Top 10 Best JavaScript eBooks that Beginners should Learn
50+ Beautiful Resources of HTML Form using CSS and JavaScript
The Ultimate JavaScript Tutorial in Web Design
HTML5 Web Workers Multithreading in JavaScript
Learn more about JavaScript Inheritance with Tiny JavaScript Example Codes


Free JavaScript Tutorials & Articles
at www.JavaScriptBank.com