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

For this, use the document.getElementByClassName(). Following is the code −Example Live Demo Document Click The Button to get an alert    for (var clickButton of    document.getElementsByClassName("clickTheButton"))    clickButton.addEventListener("click", alertMeessage);    function alertMeessage() {       alert("You have clicked the button");    } 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 −When you click the button, an alert message will be visible. This will produce the following output −

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

Following is our object −var customerDetails ={    "customerFirstName":"David",    "customerLastName":"Miller",    "customerAge":21,    "customerCountryName":"US" };Now, create a new array and use push() function. Following is the code −Examplevar customerDetails ={    "customerFirstName":"David",    "customerLastName":"Miller",    "customerAge":21,    "customerCountryName":"US" }; var customerObjectToArray = []; customerObjectToArray.push(customerDetails); console.log(customerObjectToArray);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo125.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo125.js [    {       customerFirstName: 'David',       customerLastName: 'Miller',       customerAge: 21,       customerCountryName: 'US'    } ]

Let’s say the following is our input type with value, “John Smith” −To change, use the attr() method −$('#changeTheName').attr('value', 'Please enter your name.......');You need to use the concept of attr(). Following is the code −Example Live Demo Document    $('#changeTheName').attr('value', 'Please enter your name.......'); 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 −

Let’s say the following is our file name −var actualJavaScriptFileName = "demo.js";Following is the word to be inserted before the dot extension −var addValueBetweenFileNameAndExtensions = "programming";At first, you need to split() the file name on the basis of dot(.) and then to insert a character, you can use the concept of template variables. Following is the code −Examplevar addValueBetweenFileNameAndExtensions = "programming"; var actualJavaScriptFileName = "demo.js"; console.log("The actual File name="+actualJavaScriptFileName); var [fileName, fileExtension] = actualJavaScriptFileName.split('.'); console.log("After adding into the file name="); console.log(`${fileName}- ${addValueBetweenFileNameAndExtensions}.${fileExtension}`)To run the above program, you need to use the following command −node fileName.js.OutputHere, my file name is demo124.js. ... Read More

To convert string type value to array type, use the parse() method. Following is the code −Examplevar customerDetails='[    {"name": "John", "countryName": "US"},    {"name": "David", "countryName": "AUS"},    {"name": "Bob", "countryName": "UK"} ]'; console.log("The actual value="+customerDetails); var convertStringToArray=JSON.parse(customerDetails); console.log("After converting string to array objects="); console.log(convertStringToArray);To run the above program, you need to use the following command −node fileName.js.OutputHere, my file name is demo123.js. This will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo123.js The actual value=[{"name": "John", "countryName": "US"}, {"name": "David", "countryName": "AUS"}, {"name": "Bob", "countryName": "UK"}] After converting string to array objects=[    { name: 'John', countryName: 'US' ... Read More