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Javascript Articles
Page 68 of 534
How can I remove a child node in HTML using JavaScript?
Following is the code to remove a child node in HTML using JavaScript −Example Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result { font-size: 20px; font-weight: 500; } Removing a child node in HTML using JavaScript Cow Lion Tiger Buffalo CLICK HERE Click the above button to remove the first list element from the above list let resEle = document.querySelector(".result"); let animalList = document.querySelector(".animal"); document.querySelector(".Btn").addEventListener("click", () => { animalList.removeChild(animalList.childNodes[0]); animalList = animalList; }); OutputThe above code will produce the following output −On clicking the ‘CLICK HERE’ button −
Read MoreHow can we validate decimal numbers in JavaScript?
Following is the code to validate decimal numbers in JavaScript −Example Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result { font-size: 20px; font-weight: 500; } Validate decimal numbers in JavaScript CHECK Click the above button to check if a valid decimal number is entered or not let resEle = document.querySelector(".result"); document.querySelector(".Btn").addEventListener("click", () => { var str = document.querySelector(".num").value; var regex = /^[-+]?[0-9]+\.[0-9]+$/; ...
Read MoreHow to find keys of a hash in JavaScript?
Following is the code for finding keys of a hash in JavaScript −Example Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result { font-size: 20px; font-weight: 500; } Find keys of a hash in JavaScript DISPLAY Click on the above button to display the hash keys let resEle = document.querySelector(".result"); let obj = { firstName: "Rohan", lastName: "Sharma", age: 22, }; document.querySelector(".Btn").addEventListener("click", () => { resEle.innerHTML += "object keys are " + Object.keys(obj); }); OutputThe above code will produce the following output −On clicking the ‘DISPLAY’ button −
Read MoreJavaScript program to decrement a date by 1 day
Following is the code to decrement a date by 1 day in JavaScript −Example Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result,.sample { font-size: 20px; font-weight: 500; color: rebeccapurple; } JavaScript program to decrement a date by 1 day Decrement Click on the above button to decrement the date by one day let resEle = document.querySelector(".result"); let sampleEle = document.querySelector(".sample"); let date = new Date(); sampleEle.innerHTML = date; document.querySelector(".Btn").addEventListener("click", () => { date.setDate(date.getDate() - 1); resEle.innerHTML = "New Date = " + date; }); OutputThe above code will produce the following output −On clicking the ‘Decrement’ button −
Read MoreHow to implement asynchronous loop in JavaScript?
Following is the code to implement asynchronous loop in JavaScript −Example Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result { font-size: 20px; font-weight: 500; color: blueviolet; } Asynchronous loop in JavaScript CLICK HERE Click on the above button to start our asynchronous loop let resEle = document.querySelector(".result"); async function waitTime(time) { return new Promise((resolve) => { setTimeout(resolve, time); }); } async function someFunction() { for (let i = 0; i < 10; i++) { await waitTime(2000); resEle.innerHTML += "i = " + i + ""; } } document.querySelector(".Btn").addEventListener("click", () => { someFunction(); }); OutputOn clicking the ‘CLICK HERE’ button the loop will print 1 to 10 −
Read MoreNo. of ways to empty an array in JavaScript
To empty an array in JavaScript, there are four ways −Setting to new Array − In this we set our array variable to a new empty array.Using length property − In this we set the length property of our array to 0.Using pop − In this we continuously pop the array elements till the length reaches to 0.Using splice − In this we put the start index as 0 and the no of elements to removed as array.length-1.Following is the code to display no. of ways to empty an array in JavaScript −Example Document ...
Read MorePassing parameters to callback functions JavaScript
Following is the code for passing parameters to callback functions in JavaScript −Example Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result{ font-size: 20px; font-weight: 500; color: blueviolet; } Passing parameters to callback functions CLICK HERE Click on the above button to pass parameter to callback function add2 and call it let resEle = document.querySelector(".result"); function add2(a) { return a + 2; } function multiply9(fn, num) { return fn(num) * 9; } document.querySelector(".Btn").addEventListener("click", () => { resEle.innerHTML = "The number returned = " + multiply9(add2, 8); }); OutputOn clicking the ‘CLICK HERE’ button −
Read MoreFat arrow functions in JavaScript
The fat arrow function syntax looks like the following −(param1, param2, ..)=>{ }It doesn’t have the function keyword and only have the => between the parameters and the function body.Following is the code implementing fat arrow functions in JavaScript −Example Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result{ font-size: 20px; font-weight: 500; color: blueviolet; } Fat arrow functions CLICK HERE Click on the above button to call the add() fat arrow ...
Read MoreFat vs concise arrow functions in JavaScript
The consice arrow is more stream lined form of fat arrow functions for one-line functions. If the function body only has one line of code, then there isn’t any need of curly braces {} for function body as conscie arrow functions have implicit return. Also, if there is only one parameter then that can be written without the parenthesis () but if there is no parameter then the parenthesis is necessary.SyntaxFat arrow function −let add = (a, b) =>{return a+b;}Consice arrow function:let add = (a, b)=>a+b;If one parameter only −let add = a=>a+22;Following is the code for fat vs concise ...
Read MorePseudo mandatory parameters in JavaScript
Following is the code to implement pseudo mandatory parameters in functions in JavaScript −Example Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result { font-size: 20px; font-weight: 500; color: blueviolet; } Optional function parameters CLICK HERE Click on the above button to call the add() and multiply() function let resEle = document.querySelector(".result"); function add(a = 0, b = 0) { return a + b; } function multiply(a, b) { a = a || 0; b = b || 0; return a + b; } document.querySelector(".Btn").addEventListener("click", () => { resEle.innerHTML = "Sum of the numbers = " + add() + ""; resEle.innerHTML += "Multiplication of the numbers = " + multiply() + ""; }); OutputOn clicking the ‘CLICK HERE’ button −
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