var previousTab=null;
function showTab(){
var tabEl=document.getElementById('tab'+arguments[0]);
if(!tabEl)return true;
if(previousTab)previousTab.className="hide"
tabEl.className="show"
previousTab=tabEl
}
onload=function(){
var allEls=document.getElementsByTagName("*");
var l=allEls.length;
for(var i=0;i<l;i++){
if(/^tab\d*$/.test(allEls[i].id)&&/show/.test(allEls[i].className))previousTab=allEls[i]
}
}