function changeThemBlack()
    {
        document.getElementById('mainDiv').className ="black"
    }
    function changeThemBlue()
    {
        document.getElementById('mainDiv').className ="blue"
    }
    function changeThemOrange()
    {
        document.getElementById('mainDiv').className ="orange"
    }	
    function changeThemGreen()
    {
        document.getElementById('mainDiv').className ="green"
    }	
    function changeThemViolet()
    {
        document.getElementById('mainDiv').className ="violet"
    }	
    function changeThemBrown()
    {
        document.getElementById('mainDiv').className ="brown"
    }	
    function changeThemRed()
    {
        document.getElementById('mainDiv').className ="red"
    }