The JavaScript array.keys() creates an array iterator object having only the keys of an arrayFollowing is the code for the array.keys() method −Example Live Demo Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .sample {       font-size: 20px;       font-weight: 500;    } JavaScript array keys() CLICK HERE Click on the above button to see the keys of the array    let fillEle = document.querySelector(".sample");    let arr = ["H", "E", "L", "L", "O"];    fillEle.innerHTML = arr;    arr = arr.keys();    document.querySelector(".Btn").addEventListener("click", () => {       fillEle.innerHTML = "";       for (let x of arr) {          fillEle.innerHTML += x + "";       }    }); OutputOn clicking the “CLICK HERE” button −

The JavaScript Array prototype constructor is for adding new methods and properties to array object. These properties and methods will be available for each array.Following is the code for the array prototype constructor −Example Live Demo Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .sample {       font-size: 20px;       font-weight: 500;    } JavaScript Array prototype Constructor CLICK HERE Click on the above button to convert the string to upper and lowercase alternatively    Array.prototype.upperLower ... Read More

A generator function uses the yield keyword to generate results and maintain its state even after returning so that the next time when it is called it can resume immediately from the last yield run. Each call to the generator function will send a value back to the caller.Following is the code for the Generator function in JavaScript −Example Live Demo Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .sample {       font-size: 18px;       font-weight: 500;    } JavaScript ... Read More

The findIndex() function in JavaScript returns the index of the first element value that satisfy a given condition in an array.Following is the code for the array find() function −Example Live Demo Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .findIndex {       font-size: 20px;       font-weight: 500;    } JavaScript Array FindIndex() example CLICK HERE Click on the above button to get the index of lion in the array    function findLion(animal) {       return ... Read More

The cursor property is sets or returns the cursor type that will be displayed for the cursor property.Following is the code for implementing JavaScript Cursor property −Example Live Demo    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    } JavaScript Cursor property Hover the mouse over the above paragraph after clicking the below button Change Cursor    let sampleEle = document.querySelector(".sample");    document.querySelector(".Btn").addEventListener("click", () => {       sampleEle.style.cursor = "crosshair"; }); OutputOn clicking the “Change Cursor” button −

The JavaScript Array.isArray() method is used to check if an object is an array or not.Following is the code for the Array.isArray() method −Example Live Demo Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .sample {       font-size: 20px;       font-weight: 500;    } JavaScript Array isArray() CLICK HERE Click on the above button to check if the above object is an array or not    let fillEle = document.querySelector(".sample");    let arr = ["cow", "bull", ... Read More

The JavaScript array.includes() method is used to check if an array contains a given element or not.Following is the code for the array.includes() method −Example Live Demo Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .sample {       font-size: 20px;       font-weight: 500;    } JavaScript Array includes() CLICK HERE Click on the above button to check if the array contains lion element or not    let fillEle = document.querySelector(".sample");    let arr = ["cow", "bull", "lion", "tiger", "sheep"];    fillEle.innerHTML = arr;    document.querySelector(".Btn").addEventListener("click", () => {       fillEle.innerHTML = "Lion is present in array: " + arr.includes("lion");    }); OutputOn clicking the “CLICK HERE” button −

The JavaScript focus() method is used for focusing on an element only if the element can be focused.Following is the code for the JavaScript Focus() Method −Example Live Demo Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .sample {       font-size: 18px;       font-weight: 500;    } JavaScript focus() CLICK HERE Click on the above buttons to focus the input field    let sampleEle = document.querySelector(".sample");    document.querySelector(".Btn").addEventListener("click", () => {       sampleEle.focus();    }); OutputOn clicking the “CLICK HERE” button −

The exec() method executes the search for match and if the matched text is found in the specified string then it is returned otherwise null is returned.Following is the code for the JavaScript exec() Method −Example Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .sample {       font-size: 18px;       font-weight: 500;    } JavaScript exec() Lorem ipsum dolor, sit amet consectetur adipisicing. CLICK HERE Click on the above buttons to execute regex   ... Read More

The escape() function in JavaScript is used for encoding a string. It is deprecated in JavaScript 1.5.Following is the code for the JavaScript escape()Example Live Demo Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .sample {       font-size: 18px;       font-weight: 500;    } JavaScript escape() CLICK HERE Click on the above buttons to encode the URI    let sampleEle = document.querySelector(".sample");    let url = "https://www.google.com/images?size=420px&name=8s1f.jpg";    document.querySelector(".Btn").addEventListener("click", () => {       sampleEle.innerHTML = escape(url);    }); OutputOn clicking the “CLICK HERE” button −