function exchangeDisplay(id){
	
	var elemid, elemname, vis;

	if(document.getElementById) {
		elemid = document.getElementById(id);
		//alert(elemid.className);
	}
	else if(document.all) {
		elemid = document.all[id];
		//alert("test");
	}
	else if(document.layers) {
		elemid = document.layers[id];
		//alert("test");
	}

	vis = elemid.style;
	elemname = document.getElementsByName('img_'+id)[0];
	//alert(vis.display);
	//return;
	
	if(vis.display == '' || vis.display == null) {
		vis.display = 'block';
		//vis.setProperty('display', 'block', 'important');					
		elemname.src = '/images/minus.gif';
		//vis.display = (elem.offsetWidth != 0 && elem.offsetHeight != 0) ? 'block':'none';
	}
	else if (vis.display == 'block') {
		vis.display = 'none';
		//vis.setProperty('display', 'none', 'important');
		elemname.src = '/images/plus.gif';
	}
	else if (vis.display == 'none') {
		vis.display = 'block';
		//vis.setProperty('display', 'block', 'important');
		elemname.src = '/images/minus.gif';
	}
  
}