var i=0;
function toggle_css(){
if (window.navigator.platform =="MacPPC" && document.all){
document.styleSheets[0].disabled=!document.styleSheets[0].disabled
}else{
var element = document.getElementById("css1");
if(i==0){
element.href = "check.css" 
i=1;
}else{
element.href = "base.css" 
i=0;
};
}
}