var req;

function loadHtmlDoc(url) {
	req = false;
    // branch for native XMLHttpRequest object
    if(window.XMLHttpRequest && !(window.ActiveXObject)) {
    	try {
			req = new XMLHttpRequest();
        } catch(e) {
			req = false;
        }
    // branch for IE/Windows ActiveX version
    } else if(window.ActiveXObject) {
       	try {
        	req = new ActiveXObject("Msxml2.XMLHTTP");
      	} catch(e) {
        	try {
          		req = new ActiveXObject("Microsoft.XMLHTTP");
        	} catch(e) {
          		req = false;
        	}
		}
    }
	if(req) {
		req.onreadystatechange = processReqChange;
		req.open("GET", url, true);
		req.send("");
	}
}
function processReqChange() {
    // only if req shows "loaded"
   var temp;
    if (req.readyState == 4) {
        // only if "OK"
        if (req.status == 200) {
	     temp = document.getElementById("mainDiv");
	    temp.innerHTML = req.responseText;
        } else {
            alert("There was a problem retrieving the page:\n" +
                req.statusText);
        }
    }
}