function showhidetabs(tab){var d=document;var first=d.getElementById('first');var second=d.getElementById('second');var third=d.getElementById('third');var tabfirst=d.getElementById('tabfirst');var tabsecond=d.getElementById('tabsecond');var tabthird=d.getElementById('tabthird');tabfirst.className='';tabsecond.className='';tabthird.className='';first.style.display='none';second.style.display='none';third.style.display='none';d.getElementById('tab'+tab).className='selected';d.getElementById(tab).style.display='block'}