Ajax Response

I have the following code (part of it):

ajax.onCompletion = createList;
ajax.runAJAX();

function createList()
{
	var obj = document.getElementById('myList');
	eval(ajax.response);
}

Code (markup):

I am trying to only display the second drop down only if there were actual options returned from the PHP file. I can not figure out what to test for to see if there was no response or not from the request.

It looks like even if I pass nothing from the php file, that the ajax.response returns something. I have not done JS in a while, so any help is much appreciated.

 

As I understand from your code, the ajax.response must be a javascript code string.
Please let me know the ajax.response content in 2 cases:
1 . When there is option sent from server
2. When there is no option sent from server

 

if (ajax.responseText)

Code (markup):

?