JSON Access via AJAX using JavaScript 'JSON.parse()' - Does not work in IE 6 and 7

RESULT
DATA FILE

{"employees":[
{"firstName":"John","lastName":"Doe" },
{"firstName":"Anna","lastName":"Smith" },
{"firstName":"Peter","lastName":"Jones" }
]
}


CODE

	var jsonTxt = "";
	var request = (window.XMLHttpRequest) ? new XMLHttpRequest() : new ActiveXObject("Microsoft.XMLHTTP");
	request.open("GET", "data.js", true);

	request.onreadystatechange = function()
	{
		if ((request.readyState == 4) && (request.status == 200))
		{
			jsonTxt = request.responseText;
			var jsonObj = JSON.parse(jsonTxt);			// Does NOT work in IE 6 and 7
			jLen = jsonObj.employees.length;
			var jDiv = document.getElementById("jsonDiv");
			jDiv.display = "block";
			for (v=0; v<jLen; v++)
			{
			  var contentDiv = document.createElement('DIV');
			  jDiv.appendChild(contentDiv);
			  jDiv.innerHTML += "<p style='color:blue;'>  First Name: <span>"+jsonObj.employees[v].firstName+
				"</span><br>   Last Name: <span>"+jsonObj.employees[v].lastName+"</span><br>' </p>";
			}
		}
	}

	request.send(null);