function createHTTPObject() { 
   var req;
   if(window.XMLHttpRequest){ 
      // Firefox, Safari, Opera... 
      req = new XMLHttpRequest(); 
   } else if(window.ActiveXObject) { 
      // Internet Explorer 5+ 
      req = new ActiveXObject("Microsoft.XMLHTTP"); 
   } else { 
      alert('Problem creating the XMLHttpRequest object'); 
   } 
   return req; 
} 


function changeCategory(crw) {
	var cr = sChangeCategoryMenu(crw);
	var ir = sChangeItemMenu(crw);
	var lr = sChangeContentLeft(crw);
	var rr = sChangeContentRight(crw);
}

function changeItem(crw,irw) {
	var lr = sChangeContentLeft(crw,irw);
	var rr = sChangeContentRight(crw,irw);
	var ir = sChangeItemMenu(crw,irw);
}

function changePicture(irw,pnum) {
	var rr = sChangePicture(irw,pnum);
}

function sChangeCategoryMenu(crw) {
	var result = doReplace('/portfolio/category/'+crw+'/','CategoryMenu');
   	return null;
}

function sChangeItemMenu(crw,irw) {
	var url = (!irw) ? '/portfolio/item/'+crw+'/' : '/portfolio/item/'+crw+'/'+irw+'/';
	var result = doReplace(url,'ItemMenu');
   	return null;
}

function sChangeContentLeft(crw,irw) {
	var url = (!irw) ? '/portfolio/content/left/'+crw+'/' : '/portfolio/content/left/'+crw+'/'+irw+'/';
	var result = doReplace(url,'LeftContent');
   	return null;
}

function sChangeContentRight(crw,irw) {
	var url = (!irw) ? '/portfolio/content/right/'+crw+'/' : '/portfolio/content/right/'+crw+'/'+irw+'/';
	var result = doReplace(url,'RightContent');
   	return null;
}

function sChangePicture(irw,pnum) {
	var url = (!pnum) ? '/portfolio/picture/'+irw+'/' : '/portfolio/picture/'+irw+'/'+pnum+'/';
	var result = doReplace(url,'RightContent');
   	return null;
}


function doReplace(url,id) {
	var http = createHTTPObject();
	http.open('get',url);
   	http.onreadystatechange = function() {
		if (http.readyState == 4 && http.status == 200) { 
      		var response = http.responseText;
      		// alert('response:' + response);
      		if(response) { 
				document.getElementById(id).innerHTML = http.responseText; 
      		}
   		} 
	} 
   	http.send(null);
   	
   	return null;
}