var req;
var urlBase = "http://www.elizabethjonesdesign.com/templates/includes/php/";
var resourceItem;

function loadXMLDoc(url, formItem) 
{
    // branch for native XMLHttpRequest object
    if (window.XMLHttpRequest) {
        req = new XMLHttpRequest();
		if(req.overrideMimeType) {
        	req.overrideMimeType('text/xml');
		}
		req.onreadystatechange = processReqChange;
        req.open("GET", url, true);
        req.send(null);
    // branch for IE/Windows ActiveX version
    } else if (window.ActiveXObject) {
        req = new ActiveXObject("Microsoft.XMLHTTP");
        if (req) {
            req.onreadystatechange = processReqChange;
            req.open("GET", url, true);
            req.send();
        }
    }
}

function processReqChange() 
{
    // only if req shows "complete"
    if (req.readyState == 4) {
        // only if "OK"
        if (req.status == 200) {
            // ...processing statements go here...
        	
        	response = req.responseText;
        	changePhoto('', response);    
    	        
        } else {
            alert("There was a problem retrieving the XML data:\n" + req.statusText);
        }
    }
}

function changePhoto(input, response, elementID) {
	if(response != '') {
		//Response mode
		
		element = document.getElementById(resourceItem);
		
		url = document.getElementById("photo_link");
		
		//break response into photo_url and caption if caption exists.
		var photo_url;
		var caption = "";
		var photo_link;
		
		//parse the string (photourl::photo_link:::caption)
		
		//check for the beginning of : and return the photo url.
		i = response.indexOf(':');
		photo_url = response.substring(0,i);
		
		//check if we have a caption
		if(response.search(':::') != -1) {
			i = response.search('::')+2;
			k = response.search(':::');
			photo_link = response.substring(i,k);
			caption = response.substring(k+3,response.length);
		}
		else {
			i = response.search('::')+2;
			photo_link = response.substring(i);
		}

		if(document.getElementById("photo_caption")) {
			
			var photo_caption = document.getElementById("photo_caption");
			photo_caption.innerHTML = caption;
		}
		element.src = photo_url;
		url.href = photo_link;
	
	} else {
		
		//Input mode
		//input passed in form of '4&index=1' where numbers are respective variables set by calling A tag.
		
		url=urlBase+'getPhotos.php5?id='+input;
		
		resourceItem=elementID;
		escape(url);
		loadXMLDoc(url, resourceItem);
	}
}