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Let’s say the following is our array −var details = [ { studentName: "John", studentMarks: [78, 98] }, { studentName: "David", studentMarks: [87, 87] }, { studentName: "Bob", studentMarks: [48, 58] }, { studentName: "Sam", studentMarks: [98, 98] }, ]We need to remove the duplicate property value i.e. 87 is repeating above. We need to remove it.For this, use the concept of map().ExampleFollowing is the code −var details ... Read More
For this, use the addEventListener() with mousedown event.ExampleFollowing is the code − Document document.addEventListener("mousedown", function () { console.log("Mouse down event is happening"); }); To run the above program, save the file name “anyName.html(index.html)”. Right click on the file and select the option “Open with Live Server” in VS Code editor.OutputThis will produce the following output on console −When you click the mouse, the event will generate. The console output is shown below −
At first, set a new Date in JavaScript −var dateValue = new Date("2021-01-12 10:10:20");Use new Date() along with setHours() and getHours() to add time.ExampleFollowing is the code −var dateValue = new Date("2021-01-12 10:10:20"); dateValue.setHours(dateValue.getHours() + 2); console.log("The date value is=" + dateValue.toString()); console.log("Only Hours value after incrementing=" + dateValue.getHours());To run the above program, you need to use the following command −node fileName.js. Here, my file name is demo291.js.OutputThis will produce the following output on console −PS C:\Users\Amit\javascript-code> node demo291.js The date value is=Tue Jan 12 2021 12:10:20 GMT+0530 (India Standard Time) Only Hours value after incrementing=12Read More
For this, use forEach() along with [] to an associative array.ExampleFollowing is the code −var result = {}; var names = ['John', 'David', 'Mike', 'Sam', 'Bob', 'Adam']; names.forEach((nameObject, counter) => { var generatedValues = { [nameObject]: counter }; Object.assign(result, generatedValues) }) console.log(result);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo290.js.OutputThis will produce the following output on console −PS C:\Users\Amit\javascript-code> node demo290.js { John: 0, David: 1, Mike: 2, Sam: 3, Bob: 4, Adam: 5 }
Let’s say the following is our button −Press MeOn filling the below input field, the color of the above button should change −ExampleFollowing is the code − Live Demo Document UserName: Press Me function changeTheColorOfButtonDemo() { if (document.getElementById("changeColorDemo").value !== "") { document.getElementById("buttonDemo").style.background = "green"; } else { document.getElementById("buttonDemo").style.background = "skyblue"; } } To run ... Read More
If the const is used in a program, and if you try to reassign the value to const variable then an error will arise.Let’s say the following is our const variable −const result = (first, second) => first * second;Now, we will try to reassign a value to the const variable and an erro can be seen in the output.ExampleFollowing is the code −const result = (first, second) => first * second; result = first => first =first*10; console.log(result(10, 20)); To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo284.js.OutputThis will produce ... Read More
Let’s say we have the following sample video tag on a web page You cannot play video here...... To hide a video on a web page, use yourVariableName.style.display=’none’.ExampleFollowing is the code − Document .hideVideo { display: block; z-index: 999; margin-top: 10px; margin-left: 10px; } You cannot play video here...... var hideVideo = document.getElementsByClassName("hideVideo")[0]; hideVideo.style.display = ... Read More
Let’s say the following is our unsorted array with negative and positive numbers −var arr = [10, -22, 54, 3, 4, 45, 6];ExampleFollowing is the code to implement Bubble Sort −function bubbleSort(numberArray, size) { for (var lastIndex = size - 1; lastIndex > 0; lastIndex--) { for (var i = 0; i < lastIndex; i++) { if (numberArray[i] > numberArray[i + 1]) { var temp = numberArray[i]; numberArray[i] = numberArray[i + 1]; numberArray[i + ... Read More
Let’s say the following is our array object −var arrayObject = [ "John", "David", "Mike" ]You can use length property to set the length to 0 and clear memoryThe syntax is as follows to clear memory −yourArrayObjectName.length=0; // To clear memory yourArrayObjectName.length=4; // To allocate memoryOutputThis will produce the following output on console −var arrayObject = [ "John", "David", "Mike" ] arrayObject.length = 0; console.log(arrayObject); arrayObject.length = 5; for (var i = 0; i < arrayObject.length; i++) ... Read More
You can use event listeners for clicks.ExampleFollowing is the code − Live Demo Document First Division Second Division document.addEventListener('click', callEventFuncion) function callEventFuncion(event) { var div = document.querySelectorAll('.divDemo'); var titleResult = document.querySelectorAll('.my-title'); var result = Array.apply(0, div).find((v) => v.contains(event.target)); if (result) { console.log(" Incrementing Division Selection"); } else { ... Read More