function Ajax () {
	this.req = null;
	this.url = null;
	this.method = 'GET';
	this.async = true;
	this.status = null;
	this.statusText = '';
	this.postData = null;
	this.readyState = null;
	this.responseText = null;
	this.responseXML = null;
	this.handleResp = null;
	this.responseFormat = 'text'; // 'text', 'xml', or 'object'
	this.mimeType = null;

	this.init = function () {
		if (!this.req) {
			try {
				//try to create object for FF, Safari,  IE7, etc.
				this.req = new XMLHttpRequest ();
			}
			catch (e) {
				try {
					//Try to create object for later versions of IE.
					this.req = new ActiveXObject ('MSXML2.XMLHTTP');
				}
				catch (e) {
					try {
						//Try to create object for early versions of IE.
						this.req = new ActiveXObject ('Microsoft.XMLHTTP');
					}
					catch (e) {
						// Could not create an XMLHttpREquest object.
						return false;
					}
				}
			}
		}
		return this.req;
	};
	
	this.doGet = function(url, hand, format) {
        this.url = url;
        this.handleResp = hand;
        this.responseFormat = format || 'text';
        this.doReq();
    };
    
    this.doPost = function (url, postData, hand, format) {
        this.url = url;
        this.handleResp = hand;
        this.responseFormat = format || 'text';
        this.method = 'POST';
        this.postData = postData;
        this.doReq ();
    };
	
	this.doReq = function () {
		if (!this.init ()) {
			alert ('Could not create XMLHttpRequest object.');
			return;
		}
		this.req.open (this.method, this.url, this.async);
		if (this.method == 'POST') {
		    this.req.setRequestHeader ('Content-Type', 'application/x-www-form-urlencoded');
		}
		if (this.mimeType) {
            try {
                req.overrideMimeType(this.mimeType);
            }
            catch (e) {
                // couldn't override MIME type -- IE6 or Opera?
            }
        }
		var self = this; // Fix loss-of-scope in inner function
		
		var resp = null;
		this.req.onreadystatechange = function () {
			if (self.req.readyState == 4) {
				// Do stuff to handle response
				switch (self.responseFormat) {
					case 'text':
						resp = self.req.responseText;
						break;
					case 'xml':
						resp = self.req.responseXML;
						break;
					case 'object':
						resp = req;
						break;
				}
				if (self.req.status > 199 && self.req.status < 300) {
					self.handleResp (resp);
				} else {
					self.handleErr (resp);
				}
			}
		};
		this.req.send (this.postData);
	};
	
	this.abort = function() {
        if (this.req) {
            this.req.onreadystatechange = function() { };
            this.req.abort();
            this.req = null;
        }
    };
	
	this.handleErr = function() {
	    var errorWin;
        // Create new window and display error
        try {
            errorWin = window.open('', 'errorWin');
            errorWin.document.body.innerHTML = this.responseText;
        }
        // If pop-up gets blocked, inform user
        catch(e) {
            alert('An error occurred, but the error message cannot be' +
            ' displayed because of your browser\'s pop-up blocker.\n' +
            'Please allow pop-ups from this Web site.');
        }
    };
    
    this.setMimeType = function(mimeType) {
        this.mimeType = mimeType;
    };
    
    this.setHandlerResp = function(funcRef) {
        this.handleResp = funcRef;
    };
    
    this.setHandlerErr = function(funcRef) {
        this.handleErr = funcRef; 
    };
    
    this.setHandlerBoth = function(funcRef) {
        this.handleResp = funcRef;
        this.handleErr = funcRef;
    };
}