problems with elements visualization in IE7

[agam84]

Ciao,
this function should show only selected items, in firefox always works, but with IE works only the first time, then are visualized all the elements visualized previusly

function showMapLegend(id){
			alert(id);
			var elem=document.getElementById(id);
			var tohide=document.getElementsByName('legend');
			for(var i=0;i<tohide.length;i++){
			
				tohide[i].style.display='none';
			}
			elem.style.display = '';