How to create new object in javascript

How to create new object in javascript?

View demo

<div id="colorShowContainer"></div><br>

<div id="colorShowContainer1"></div><br>

<div id="colorShowContainer2"></div>

        <script>

        var colors = {

          firstColor: "Red",

          secondColor : "Green",

          thirdColor : "Blue",

         

          completeColor : function() {

            return this.firstColor + " " + this.secondColor + " " + this.thirdColor;

          }

        };

        // How to access first trick

        document.getElementById("colorShowContainer").innerHTML = colors.firstColor + " " + colors.secondColor;

        // How to access second trick

        document.getElementById("colorShowContainer1").innerHTML = colors['firstColor'] + " " + colors['secondColor'];

        // How to access method from the object

        document.getElementById("colorShowContainer2").innerHTML = colors.completeColor();

        </script>