var xmlhttp=false;
/*@cc_on @*/
/*@if (@_jscript_version >= 5)
// JScript gives us Conditional compilation, we can cope with old IE versions.
// and security blocked creation of the objects.
 try {
  xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
 } catch (e) {
  try {
   xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
  } catch (E) {
   xmlhttp = false;
  }
 }
@end @*/
if (!xmlhttp && typeof XMLHttpRequest!='undefined') {
	try {
		xmlhttp = new XMLHttpRequest();
	} catch (e) {
		xmlhttp=false;
	}
}
if (!xmlhttp && window.createRequest) {
	try {
		xmlhttp = window.createRequest();
	} catch (e) {
		xmlhttp=false;
	}
}

var isLoading = false;

function changeTab(file, current) {
	if(isLoading == true) { return; }
	isLoading = true;

  if(current != undefined) {
		/* "close" all tabs */
		var menuItems = document.getElementById('menuItem').getElementsByTagName('a');
		for(var i=0;i<menuItems.length;i++) {
			menuItems[i].className = "";
		}
		/* open pressed tab */
		current.className = 'selected';
		current.blur();
	}

	/* set please wait to content */
  var content = document.getElementById('content')
	content.innerHTML = "<br /><br /><center>Loading.<br /><img src='style/gfx/loading.gif' alt='Loading page' /></center><br /><br />";
	
	/* create file */
	var fullFile = "pages/page_"+file+".php";
	
	/* fetch file requested */
	xmlhttp.open("GET", fullFile, true);
	xmlhttp.onreadystatechange = function() {
		if (xmlhttp.readyState==4) {
			document.getElementById('content').innerHTML = xmlhttp.responseText;
			isLoading = false;
		}
	}
	xmlhttp.send(null)
}