function changeFont(font) {
    var ss = document.all ? document.styleSheets[0].rules : document.styleSheets[0].cssRules;  //ie : ff
    ss[0].style.fontFamily = font;
}
function changeFontSize(size) {
    if (size == 1)
        size = 12;
    else if (size == 2)
        size = 16;
    else if (size == 3)
        size = 20;
    var ss = document.all ? document.styleSheets[0].rules : document.styleSheets[0].cssRules;  //ie : ff
//    var t = document.styleSheets[0].rules.length;
//    alert(t);
    ss[0].style.fontSize = size + "px";
}

//function changeFontSize(size) {
//    var ss = document.all ? document.styleSheets[0].rules : document.styleSheets[0].cssRules;  //ie : ff
//    if (size == 1)
//        ss[0].style.font = "medium ss[0].style.fontFamily";
//    else if (size == 2)
//        ss[0].style.font = "x-large ss[0].style.fontFamily";
//    else if (size == 3)
//        ss[0].style.font = "xx-large ss[0].style.fontFamily";
//}