ns4 = document.layers;
ie = document.all;
moz = document.getElementById && !document.all;
	 
function changeFontSize (id, isIncrease) 
{
    // 1 = increase
    // 0 = decrease
    var obj;
    var size; 

    if (ns4) 
    { 
        alert ("Sorry, but NS4 does not allow font changes."); return false;
    }
    else if (ie) 
    {
        obj = document.getElementById(id);
        size = obj.currentStyle.fontSize;
	
	if (isIncrease) 
	{
	    size = parseFloat(size) + .2;
	} 
	else 
	{
	    size = parseFloat(size) - .2;
	}  
	obj.style.fontSize = size + "em";

    }
    else if (moz) 
    {
	obj = window.getComputedStyle(document.getElementById(id), ''); 
	size = obj.getPropertyValue('font-size');  // value only in px
	
        if (isIncrease) 
        {
            size = size = parseFloat(size) + 2; // increase 	
	} 
        else
        {
            size = size = parseFloat(size) - 2; // decrease
	}
        document.getElementById(id).style['fontSize'] = size + "px";
    }

    if (!obj)
    {
        alert("unrecognized ID"); return false;
    }
    return true;
}