add to array from index to end javascript code example

Example 1: javascript insert item into array

var colors=["red","blue"];
var index=1;

//insert "white" at index 1
colors.splice(index, 0, "white");   //colors =  ["red", "white", "blue"]

Example 2: addItem(item) js

function addItem(){
    var ul = document.getElementById("dynamic-list");
    var candidate = document.getElementById("candidate");
    var li = document.createElement("li");
    li.setAttribute('id',candidate.value);
    li.appendChild(document.createTextNode(candidate.value));
    ul.appendChild(li);
}

function removeItem(){
    var ul = document.getElementById("dynamic-list");
    var candidate = document.getElementById("candidate");
    var item = document.getElementById(candidate.value);
    ul.removeChild(item);
}