Amount of bitstrings that are of length 10 and that do not contain "11". There are 144 such possibilities.

countingBitString.js

/*
    Written by: Alastair Paragas
    Run the program by copy/pasting this code to http://repl.it/languages/JavaScript.
    This program finds how many bitstrings of length 10 does not contain a set of two consecutive 1s
*/

(function (window) {
    'use strict';
    
    var binaryRepresentation,
        binaryPossibilities = [],
        i;
    
    /*
        0 in decimal is 0000000000 in binary (smallest bitstring of length 10)
        1023 in decimal is 1111111111 in binary (largest bitstring of length 10)
    */
    for (i = 0; i <= 1023; i++) {
        binaryRepresentation = Number(i).toString(2);
        // BitString does not contain two consecutive 1s
        if (binaryRepresentation.indexOf('11') === -1) {
            binaryPossibilities.push(binaryRepresentation);
        }
    }
    
    window.console.log("The amount of bitstrings of length 10 that do not contain '11' are " 
        + binaryPossibilities.length + ".");
    
}(window));
// Prevent global namespace pollution through self-executing function