add to a list in a list in a list javascript code example

Example 1: javascript append element to array

var colors= ["red","blue"];
	colors.push("yellow");

Example 2: push only elements list into another list javascript

//Server side (nodeJs):
var a = [1,2,3];
a.push.apply(a, [4,5]);
//Client side (most browsers)
var arrayA = [1, 2];
var arrayB = [3, 4];
var newArray = arrayA.concat(arrayB);