function getElementsByClassName(c)
{
            for(var i=0,a=[],d;d=document.getElementsByTagName('*')[i++];){
                if(RegExp('\\b'+c+'\\b','gi').test(d.className)){
                    a.push(d);
                }
            }
            return a;
}

function showhide(id)
{

el = getElementsByClassName('tohide')

for(i=0; i<el.length; i++)
{
	el[i].style.display="none";
}

document.getElementById(id).style.display="block";



}