// A key map of allowed keys
var allowedKeys = {
    8:  'backspace'
};

// The sequence
var oopsCode = ['backspace'];

// A variable to remember the 'position' the user has reached so far.
var oopsCodePosition = 0;

// Add keydown event listener
document.addEventListener('keydown', function (e) {
    // Get the value of the key code from the key map
    var key = allowedKeys[e.keyCode];
    // Get the value of the required key from the oops Code
    var requiredKey = oopsCode[oopsCodePosition];

    // Compare the key with the required key
    if (key == requiredKey) {

        // Move to the next key in the oops Code sequence
        oopsCodePosition++;

        // Ff the last key is reached, activate cheats
        if (oopsCodePosition == oopsCode.length) {
            activateCheats();
            oopsCodePosition = 0;
        }
    } else {
        oopsCodePosition = 0;
    }
});

function activateCheats() {

    window.location.href = "/oops.html";
}