var $3 = function(i){return document.getElementById(i);}
var ua = navigator.userAgent.toLowerCase();
var isIE = (ua.indexOf("msie") > -1),isIE7 = (ua.indexOf("msie 7") > -1),isOpera = (ua.indexOf("opera") > -1),isSafari = (ua.indexOf("webkit") != -1 || ua.indexOf("khtml") != -1),isGecko = (!isSafari && ua.indexOf("gecko") > -1);


var switchpage = function(o, n, p){
   var ol = $3(o+p);
   var cl = $3(o+n);
   ol.style.display="none";
   cl.style.display="";
}

var p1 = 1;
function page1(num){   
   switchpage("p1_", num, p1);
   p1 = num;
}