You can use the concept of Map(). In JavaScript, map has the key value concept in which key must be unique.We also need to use the join() method to join Map values. Following is the code −Examplelet queryStringAppendWithURL = new Map(); queryStringAppendWithURL.set("firstParamter", ["name=John", "age=23", "countryName=US"]); queryStringAppendWithURL.set("secondParamter", ["subjectName=JavaScript", "Marks=91"]); let appendValue = Array.from(queryStringAppendWithURL.values()).map(value => value.join('?')).join('?'); console.log("The appended value is="+appendValue);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo78.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo78.js The appended value is=name=John?age=23?countryName=US?subjectName=JavaScript?Marks=91Read More

To conditionally change object property, use the logical AND operator ( &&).If both the operands are non-zero, then the condition becomes true in JavaScript’s logical AND operator.Examplelet marksDetails = { Mark1: 33, Mark2: 89 }, isBacklog = false; console.log("Result when backlog is set to false==="); console.log({ ...marksDetails, ...isBacklog === true && { Mark1: 33 }}); isBacklog = true; console.log("Result when backlog is set to true==="); console.log({ ...marksDetails, ...isBacklog === true && { Mark1: 93 }});To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo77.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> ... Read More

To remove leading zeroes in an array, use the concept of filter(). Following is our input wherein we will remove the leading zeroes −[10,0,12,0,0]) [0,0,0,0,0,0,10,12,0]) [12,0,0,1,0,0])Exampleconst removeLeadingZero = input => input.filter((lastValue => value => lastValue= lastValue || value) (false) ); console.log(removeLeadingZero([10,0,12,0,0])); console.log(removeLeadingZero([0,0,0,0,0,0,10,12,0])); console.log(removeLeadingZero([12,0,0,1,0,0]));To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo76.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo76.js [ 10, 0, 12, 0, 0 ] [ 10, 12, 0 ] [ 12, 0, 0, 1, 0, 0 ]

To change value of input, use the concept of document. The syntax is as follows −document.yourFormName.yourTextName.value=anyValue;Let’s say the following is our input type calling submitForm() on clicking “Submit Form” −         The submitForm() function changing the value of input −function submitForm(){    document.studentForm.txtInput.value='STUDENT-100'; }Example Live Demo Document    function submitForm(){       document.studentForm.txtInput.value='STUDENT-100';    } 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 ... Read More

If onclick not working for two or more links, then use the document.querySelectorAll() in JavaScript. Following is the code −Example Live Demo Document www.example.com www.test.com    const values = document.querySelectorAll('[class=class1]');    values.forEach(function(v) {       console.log(v.innerHTML);    }); 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 check if the input is a number or letter, use the isNaN() function from JavaScript. It returns true if the value is NaN i.e. Not a Number. Following is the code −Example Live Demo Document Enter the value:    function checkInputIsNumber(){       var value=document.forms["checkingInput"]["txtValue"].value;       if (isNaN(value)){          alert("Please Provide the input as a number");          return false;       }    } To run the above program, save the file ... Read More

To check if array element contains a false value, you can use the Object.values() in JavaScript. Following is the code −Exampleconst details = [    {       customerDetails:       [          {             isMarried: true          },          {             isMarried: true          }       ]    },    {       customerDetails:    [       {             isMarried: true          },          {          isMarried: true          }       ]    } ] const isNotMarried = Object.values(details) .some(({customerDetails})=>customerDetails.some(({isMarried})=>!isMarrie d)); console.log(isNotMarried);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo75.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo75.js false

You need to use async and await with body onLoad attribute Following is the code −index.htmlExample Live Demo Document    async function callFunction(){       await testFunction();    }    function testFunction(){       console.log("Hi...");    } 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 −

For this, use toUpperCase() along with toLowerCase(). Following is the code −Examplefunction capitalEveryFirstletter(subjectTitle) {    return subjectTitle.split(' ')    .map(st => st.charAt(0).toUpperCase() + st.slice(1).toLowerCase())    .join(' ');; } var subjectTitle="iNtroduction tO JavaScript ProgRAMMINg"; var output=capitalEveryFirstletter(subjectTitle); console.log("The result="+output);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo74.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo74.js The result=Introduction To JavaScript Programming

To create a global variable, you need to place variable inside the tag. Following is the code −Example Live Demo Document checkGlobalVariable    var globalVariable;    $(document).ready(function() {       function initializeGlobalVariable() {          globalVariable = [{             "name":"John",             "age":23          }];       }       initializeGlobalVariable();    });    function createGlobalVariable() {       if (globalVariable.length) {          console.log('The Global variable name   ... Read More