Web Development Articles - Page 435 of 1049

Extracting values between various square brackets can be done using JavaScript regular expressions. The regular expressions in JavaScript are useful for extracting values enclosed within different types of brackets, such as square brackets ([ ]), curly brackets ({ }), and parentheses "( )". In this article, we'll look at how to use JavaScript's RegExp to find and get content that is inside square brackets easily. Understanding JavaScript RegExp Regular expressions (RegExp) are patterns used to match and manipulate strings in JavaScript. JavaScript RegExp helps you find and get text that is inside specific brackets by using patterns. The ... Read More

No, the parent object won’t get updated. Use Object.assign() with some parameters and check. Following is the code −Examplevar firstObject = { name: 'John' }; var secondObject = { name: 'Carol' }; console.log("Before merging="); console.log(firstObject); var afterMerging = Object.assign({}, firstObject, secondObject); afterMerging.name = 'Smith'; console.log("After merging="); console.log(firstObject);To run the above program, you need to use the following command −node fileName.js.OutputHere, my file name is demo131.js. This will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo131.js Before merging= { name: 'John' } After merging= { name: 'John' }

To check for case insensitive values, use regular expression in JavaScript. Following is the code −Examplevar allNames = ['john','John','JOHN']; var makeRegularExpression = new RegExp(allNames.join( "|" ), "i"); var hasValue = makeRegularExpression.test("JOHN"); console.log("Is Present="+hasValue);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo130.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo130.js Is Present=true

Let’s the following is our input type, wherein the user will search −Now, use hide() and show() to display only relevant search and hide rest. For example, on typing “Ja”, related keywords like “Java” and “JavaScript” should be visible because it begins with “Ja”.Example Live Demo Document Enter the keyword.. JavaScript John Smith Java David Miller -1) {             $(this).show();             $(this).prev('.subjectName').last().show();          } else {             $(this).hide();     ... Read More

Let’s say the following is our table with product quantity records − qty: qty: qty: qty: Let us now hide using the hide() method. Following is the code −Example Live Demo Document qty: qty: qty: qty:    $('.hideRowContainingZeroValue input').filter(function(){       return +this.value === 0;    }).closest("tr").hide() To run the above program, save the file name “anyName.html(index.html)” and right click on the file. Select the option “Open with Live Server” in VS Code editor.OutputThis will produce the following output −

You need to use currentDate with the help of new Date().getDate(). The syntax is as follows −var anyVariableName= yourCurrentDate - yourSubstractDateOfCurrentMonth;Examplevar currentDate=new Date().getDate(); var substractDate=new Date("2020-07-01").getDate(); const numberOfDaysInCurrentMonthOnly = currentDate-substractDate; console.log(numberOfDaysInCurrentMonthOnly);NoteToday’s date is - 28-07-2020To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo129.jsPS C:\Users\Amit\JavaScript-code> node demo129.js 27

An alert in JavaScript is a dialog box that is displayed to the user when some important information or warnings needs to be notified. It may contain a message along with OK button. When you click on the OK button, it will dismiss the dialog. Clicking a button triggers an event handler which invoke a function that instructs the browser to display a dialog with a message. In this article, we will explore a few ways to get an alert to appear when user click on a button. For example, click on the button given below to get an ... Read More

Let’s say, we have subject records with the time when we are planning to study them −const scheduleDetails = [    { subjectName: 'JavaScript', studyTime: '5 PM - 11 PM' },    { subjectName: 'MySQL', studyTime: '12 AM - 4PM' } ]Here is how we can use the map(). Following is the code −Exampleconst scheduleDetails = [    { subjectName: 'JavaScript', studyTime: '5 PM - 11 PM' },    { subjectName: 'MySQL', studyTime: '12 AM - 4PM' } ] function timeToReadSubjectName(scheduleDetails) {    var currentTime = new Date().getHours();    let result = '';    scheduleDetails.map(obj => {       ... Read More

To format HSON string in JavaScript, use JSON.stringify() with some parameters. Following is the code −Examplevar details = {    studentId: 101,    studentFirstName: 'David',    studentLastName: 'Miller',    studentAge:21,    subjectDetails: {       subjectId: 'JavaScript_101',       subjectName: 'Introduction to JavaScript',    } }; console.log("Not Pretty JSON Format=") console.log(JSON.stringify(details)); console.log("Pretty JSON Format=") console.log(JSON.stringify(details, null, 3));To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo127.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo127.js Not Pretty JSON Format= {"studentId":101, "studentFirstName":"David", "studentLastName":"Miller", "studentAge":21, "subj ectDetails":{"subjectId":"JavaScript_101", "subjectName":"Introduction to JavaScript"}} Pretty ... Read More

To check for consecutive numbers like 100, 101, 102, etc., use the concept of reduce(). TRUE would be returned for consecutive numbers, else false is the return value.Exampleconst sequceIsConsecutive = (obj) => Boolean(obj.reduce((output, lastest) => (output ? (Number(output.number) + 1=== Number(lastest.number) ? lastest : false) : false))); console.log("Is Consecutive="+sequceIsConsecutive ([{ number: '100' }, {number: '101'} ,{number: '102' }])); console.log("Is Consecutive="+sequceIsConsecutive([{ number: '100' }, {number: '102'} ,{number: '104' }]));To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo126.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo126.js Is Consecutive=true Is Consecutive=falseRead More