function fontUp()
{
    var currentNum=document.getElementById("wrap").className;
    currentNum = parseInt(currentNum.replace("wrap",""));
    
    if(currentNum < 4 ){
        document.getElementById("wrap").className="wrap" + (currentNum + 1);
        document.getElementById("FontDown").style.color = "";
    }
    if(currentNum+1 == 4)
        document.getElementById("FontUp").style.color = "#ccc";
  
}

function fontDown()
{
    
    var currentNum=document.getElementById("wrap").className;
    currentNum = parseInt(currentNum.replace("wrap",""));
    if(currentNum > 0 ){
        document.getElementById("wrap").className="wrap" + (currentNum - 1);
        document.getElementById("FontUp").style.color = "";
    }    
    if(currentNum-1 == 0)
        document.getElementById("FontDown").style.color = "#ccc";    
}