Let’s say the following is our table − Name Age John21 David22 Bob20 Mike24 To get row count of an HTML table, use .rows.length. Following is the code −Example Live Demo Document Name Age John21 David22 Bob20 Mike24    var allTableData = document.getElementById("tblDemo");    var totalNumbeOfRows = allTableData.rows.length;    console.log("Total Number Of Rows="+totalNumbeOfRows); 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 −

To set an element and it’s text, use the text() method in jQuery. With that, use the :nth-child selector to place it at a particular position. Following is the code −Example Live Demo Document JavaScript MySQL MongoDB Java C#    $('h1:nth-child(4)').text("Python"); 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 −

To group JSON data, you need to extract all the keys and use the push(). Following is the code −Examplevar details= {    "1":    {       name:"John"    },    "2":    {       name:"John"    },    "3":    {       name:"David"    }    var objectWithGroupByName = {};    for (var key in details){       var name = details[key].name;    if (!objectWithGroupByName[name]){       objectWithGroupByName[name] = [];    }    objectWithGroupByName[name].push(details[key]); } console.log(objectWithGroupByName);To run the above program, you need to use the following command −node fileName.js.OutputHere, my file name is demo122.js. This will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo122.js {    John: [ { name: 'John' }, { name: 'John' } ],    David: [ { name: 'David' } ] }

Let’s say the following is our variable −var message = 'This is the Class Demo';Following is our object, var object = new FirstClass(message)The class FirstClass −class FirstClass{    constructor( message){       this.message = message;    } }We will use eval() to call a JavaScript class object with variable. Following is the code −Exampleclass FirstClass{    constructor( message){       this.message = message;    } } var message = 'This is the Class Demo'; var object = new FirstClass(message) console.log(eval(object).message);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo121.js.OutputThis ... Read More

The ENTER has the key code 13. We will use the event.keycode to check whether ENTER is pressed or not. Following is the code −Example Live Demo Document    document.getElementById("name").addEventListener("keydown",    function(event) {       if (!event) {          var event = window.event;       }          event.preventDefault();       if (event.keyCode == 13){          login();       }    }, false);    function login(){       console.log("submitted successfully....");    } To run the ... Read More

Let’s say the following is our comma separated text in div − This, is, the, first, JavaScript, program To convert comma separated text into separate lines, you need to use trim() along with split() on the basis of comma(, ).Example Live Demo Document This, is, the, first, JavaScript, program    var allTheData = document.querySelector('.commaSeparated').textContent.trim().split(', ')    var separateList = ''    allTheData.forEach(function(value) {       separateList += '' + value + '';    });    separateList += '';    document.querySelector(".commaSeparated").innerHTML = separateList; To run the ... Read More

Let’s say the following is our nested objects −var details = [    {       id:"101",       firstName:"John",       lastName:"Smith",       age:25,       countryName:"US",       subjectDetails: {          subjectId:"Java-101",          subjectName:"Introduction to Java"       },    },    {       "uniqueId": "details_10001"    } ]Use map() along with typeOf to access nested objects. Following is the code −Examplevar details = [    {       id:"101",       firstName:"John",       lastName:"Smith",       ... Read More

Let’s say the following is our object −var details = {    firstName: 'John',    lastName: '',    countryName: 'US' }Use Object.keys() along with find() to get the key name with empty value. Following is the code −Examplevar details = {    firstName: 'John',    lastName: '',    countryName: 'US' } var result = Object.keys(details).find(key=> (details[key] === '' || details[key] === null)); console.log("The key is="+result);To run the above program, you need to use the following command −node fileName.js.OutputHere, my file name is demo118.js. This will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo118.js The key is=lastNameRead More

Let’s say the following is our object −var apiJSONObject = [    {subjectName:"MySQL"},    {subjectName:"Java"},    {subjectName:"JavaScript"},    {subjectName:"MongoDB"} ]Let’s check for existence of a value “JavaScript” −Examplevar apiJSONObject = [    {subjectName:"MySQL"},    {subjectName:"Java"},    {subjectName:"JavaScript"},    {subjectName:"MongoDB"} ] for(var i=0;i node demo117.js The search found in JSON Object

Let’s see an example wherein we are validating input text onsubmit −Example Live Demo Document    function validateTheForm(){       var validation = (document.getElementById('txtInput').value == 'gmail');       if(!validation){          alert('Something went wrong...Plese write gmail intext box and click');          return false;       }       return true;    } 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” ... Read More