how to find last index in javascript code example

Example 1: Javascript get last item in array

var colors = ["red","blue","green"];
var green = colors[colors.length - 1]; //get last item in the array

Example 2: javascript code for find the last element in array

if (loc_array[loc_array.length - 1] === 'index.html') {
   // do something
} else {
   // something else
}