function addLoadEvent(func) {
	var oldonload=window.onload;
	if(typeof window.onload!='function')	{
			window.onload=func;
	}	
	else{
		window.onload=function()	{
			oldonload();func();
		}
	}
}

registration = {
	
	el_hasMatadorID: null,
	el_usernameID: null,
	hasMatadorID: null,
	
	init: function() {
		registration.setHasMatadorID();
		registration.setUsernameID();
		registration.initEvents();
		
	},
	
	setHasMatadorID: function()	{
		registration.el_hasMatadorID = document.getElementById('input_matador_id');
	},
	
	setUsernameID: function() {
		registration.el_usernameID = document.getElementById('input_username');
	},
	
	initEvents:function()	{
		
		// add onchanges to each of the checkboxes
		if (registration.hasMatadorID == null)	{
			registration.hasMatadorID = document.getElementsByName('contact[has_matador_id]');
		}
		
		var current_matador_id_selection = 0;
		
		for (var i=0; i < registration.hasMatadorID.length; i++)	{
			
			current_matador_id_selection = registration.hasMatadorID[i];
			
			if (current_matador_id_selection.value == 1 && current_matador_id_selection.checked)	{
				registration.el_hasMatadorID.className = 'show_label';
				registration.el_usernameID.className = 'hide_label';
			}
			
			if (current_matador_id_selection.value == 0 && current_matador_id_selection.checked)	{
				registration.el_hasMatadorID.className = 'hide_label';
				registration.el_usernameID.className = 'show_label';
			}
			
			(function() {
				var oc = registration.hasMatadorID[i];
				oc.onclick = function() {
					if (oc.value == 1 && oc.checked)	{
						registration.el_hasMatadorID.className = 'show_label';
						registration.el_usernameID.className = 'hide_label';
					}
					else	{
						registration.el_hasMatadorID.className = 'hide_label';
						registration.el_usernameID.className = 'show_label';
					}
				}
			})();
		}
	},
	
	checkAll: function(el_collection, checkValue)	{
		
		for (var i=0; i < el_collection.length; i++)	{
			if (typeof(el_collection[i]) == 'object')	{
				if (el_collection[i].value == checkValue)	{
					el_collection[i].checked = 1;
				}
				else	{
					el_collection[i].checked = 0;
				}
			}
		}
	}
}
addLoadEvent(registration.init);