myArray.splice(index, itemsToDelete, item1ToAdd, item2ToAdd, ...)
Array.prototype.insert = function ( index, item ) { this.splice( index, 0, item ); };
var fruits = ["Banana", "Orange", "Apple", "Mango"]; document.getElementById("demo").innerHTML = fruits; function myFunction() { fruits.splice(2, 0, "Lemon", "Kiwi"); document.getElementById("demo").innerHTML = fruits; }