Use return statement to assign function to variables. Following is the code −Example Live Demo Document    .demo {       background: skyblue;       height: 20px;       width: 75%;       margin: 10px;       padding: 10px;    } John Smith David Miller Adam Smith    var studentNames = function() {       var names = [];       $(".demo").each(function() {          names.push($(this).data('st'));       });       return names.join();    };    console.log( studentNames() ); 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 fetch value from alert pop up, use alert(). At first, use prompt() to input the value from user. Following is the code −Example Live Demo Document    var value = prompt("Please enter an integer value");    var multiplyBy10=10*value;    alert("Result after multiplying by 10 = "+ multiplyBy10); 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 −Put an integer value and click the OK button.After clicking the OK button, the snapshot is as follows −

To detect the screen resolution, use the concept of window.screen.For width, use the following −window.screen.availWidthFor height −window.screen.availHeightFollowing is the code to detect the screen resolution −Example Live Demo Document    console.log("Available Width="+window.screen.availWidth);    console.log("Available Height="+window.screen.availHeight); 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 −

The new keyword creates an object in JavaScript. To access values, use the dot notation. Following is the code −Examplefunction newObjectCreation() {    this.firstName = "John"; } var newObject = new newObjectCreation(); newObject.firstName="David"; console.log("The first name="+newObject.firstName);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo134.jsOutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo134.js The first name=David

To attach event, use document.addEventListener() in JavaScript. Following is the code −Example Live Demo Document    document.addEventListener('click',function(event){       if(event.target && event.target.id== 'buttonSubmit'){          console.log("Event generation on the button click")       }    }); 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 −After clicking the submit button, the screenshot is as follows −

Let’s say the following is our string −var sentence = "My, , , , , , , Name, , , , is John ,, , Smith";Use regular expression along with split() and join() to remove extra spaces and commas. Following is the code −Examplevar sentence = "My, , , , , , , Name, , , , is John ,, , Smith"; console.log("Before removing extra comma and space="+sentence); sentence = sentence.split(/[\s, ]+/).join(); console.log("After removing extra comma and space="); console.log(sentence)To run the above program, you need to use the following command −node fileName.js.OutputHere, my file name is demo133.js. This will produce ... Read More

Use document.getElementById() and display using innerHTML. Following is the code −Example Live Demo Document    var jsonObject="name";    var value = jsonObject.split(" ");    var add = {};    value.forEach(function(v){       add[v] ? add[v]++ : add[v] = "John";    });    document.getElementById("objectId").innerHTML = JSON.stringify(add); 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 −

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