Javascript collaplseable div works in FF but not in IE

[sciencebear]

I have a section on my website where I can show/hide a div tag by clicking on a link. It works fine in FF, but when I try to load IE7 the script no longer works. I can't seem to figure out why.

 

//here you place the ids of every element you want.
var ids=new Array('a1','a2','a3','a4','a5','a6');

function switchid(id){	
hideallids();
showdiv(id);
}

function hideallids(){
//loop through the array and hide each element by id
for (var i=0;i<ids.length;i++){
	hidediv(ids[i]);
}		  
}

function hidediv(id) {
//safe function to hide an element with a specified id
if (document.getElementById) { // DOM3 = IE5, NS6
	document.getElementById(id).style.display = 'none';
}
else {
	if (document.layers) { // Netscape 4
		document.id.display = 'none';
	}
	else { // IE 4
		document.all.id.style.display = 'none';
	}
}
}

function showdiv(id) {
//safe function to show an element with a specified id
	  
if (document.getElementById) { // DOM3 = IE5, NS6
	document.getElementById(id).style.display = 'block';
}
else {
	if (document.layers) { // Netscape 4
		document.id.display = 'block';
	}
	else { // IE 4
		document.all.id.style.display = 'block';
	}
}
}

 

any suggestions as to why?