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Front End Technology Articles
Page 639 of 652
How to allocate memory in Javascript?
Regardless of the programming language, memory life cycle is pretty much always the same −Allocate the memory you needUse the allocated memory (read, write)Release the allocated memory when it is not needed anymoreThe second part is explicit in all languages. Use of allocated memory needs to be done by the developer.The first and last parts are explicit in low-level languages like C but are mostly implicit in high-level languages like JavaScript.Hence there is no explicit way to allocate or free up memory in JavaScript. Just initializing objects allocates memory for them. When the variable goes out of scope, it is ...
Read MoreExplain the event flow process in Javascript
In the JavaScript, Event Flow process is completed by three concepts −Event Target − The actual DOM object on which the event occured.Event Bubbling − Explained belowEvent Capturing − Explained belowEvent bubbling is the order in which event handlers are called when one element is nested inside a second element, and both elements have registered a listener for the same event (a click, for example). With bubbling, the event is first captured and handled by the innermost element and then propagated to outer elements.With capturing, the event is first captured by the outermost element and propagated to the inner elements.Let's ...
Read MoreHow to create a custom object in JavaScript?
To create a custom object in JavaScript, try the following code Example var dept = new Object(); dept.employee = "Amit"; dept.department = "Technical"; dept.technology = "Java"; document.getElementById("test").innerHTML = dept.employee + " is working on " + dept.technology + " technology.";
Read MoreHow to use OR condition in a JavaScript IF statement?
To use OR condition in JavaScript IF statement, use the || operator i.e Logical OR operator. If any of the two operands are non-zero, then the condition becomes true. Here's how you can use the operator || in JavaScript Example var a = true; var b = false; document.write("(a || b) => "); result = (a || b); document.write(result);
Read MoreHow to convert a string to camel case in JavaScript?
Camel case is the practice of writing phrases such that each word or abbreviation in the middle of the phrase begins with a capital letter, with no intervening spaces or punctuation. For example, Concurrent hash maps in camel case would be written as −ConcurrentHashMapsWe can implement a method to accept a string in JavaScript to convert it to camel case in the following way −Examplefunction camelize(str) { // Split the string at all space characters return str.split(' ') // get rid of any extra spaces using trim .map(a => a.trim()) ...
Read MoreWhat is the difference between == and === in JavaScript?
Double equals (==) is abstract equality comparison operator, which transforms the operands to the same type before making the comparison. For example,4 == 4 // true '4' == 4 //true 4 == '4' // true 0 == false // trueTriple equals (===) are strict equality comparison operator, which returns false for different types and different content.For example,4 === 4 // true 4 === '4' // false var v1 = {'value':'key'}; var v2 = {'value': 'key'}; v1 === v2 //false
Read MoreDifferences between web-garden and a web-farm in Javascript
Web Garden is the web hosting system which comprises of multiple “processes”. This means that we have a single server on which we run multiple processes. This type of hosting provides logical scalability to our web applications.Web Farm is the web hosting system which comprises of multiple “computers”. This is different from web-garden as web garden runs on a single server while a web farm runs across multiple servers. This provides physical scalability to out web applications. This type of set up is achieved using Load balancers to balance calls coming to the server using a dedicated process that forwards ...
Read MoreConvert the string of any base to integer in JavaScript
The parseInt function available in JavaScript has the following signature −parseInt(string, radix);Where, the paramters are the following −String − The value to parse. If this argument is not a string, then it is converted to one using the ToString method. Leading whitespace in this argument is ignored.Radix − An integer between 2 and 36 that represents the radix (the base in mathematical numeral systems) of the string.So we can pass the string and the radix and convert any numbner with base from 2 to 36 to integer using this method.Exampleconsole.log(parseInt("100", 10)) console.log(parseInt("10", 8)) console.log(parseInt("101", 2)) console.log(parseInt("2FF3", 16)) console.log(parseInt("ZZ", 36))Output100 8 ...
Read MoreWhat is "undefined x 1" in JavaScript?
This is not a feature of JavaScript but is Chrome's way of displaying uninitialized indexes in arrays (and array-like objects). For example, if you console.log the following −Exampleconsole.log(Array(100))Output[undefined × 100]This is better than printing [undefined, undefined, undefined,...] as it is more readable.
Read MoreWhy is javascript called Richer Interface?
JavaScript allows you to add very advanced features to your web applications. For example, Drawing and manipulating graphicsAudio and Video APIs like HTMLMediaElement, the Web Audio API, and WebRTC allow you to do really interesting things with multimedia such as creating custom UI controls for playing audio and video, displaying text tracks like captions and subtitles along with your videos, grabbing video from your web camera to be manipulated via a canvas (see above) or displayed on someone else's computer in a web conference, or adding effects to audio tracks (such as gain, distortion, panning, etc).Device APIs are basically APIs ...
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