var aXmlHttp = new Array() ;
var aXmlResponse = new Array() ;

function xmlResult() {
	for( var i = 0; i < aXmlHttp.length; i++ ) {
		if( aXmlHttp[i] && aXmlHttp[i][0] && aXmlHttp[i][0].readyState == 4 && aXmlHttp[i][0].responseText ) {
			//must null out record before calling function in case
			//function invokes another xmlHttpRequest.
			var f = aXmlHttp[i][2] ;
			var o = aXmlHttp[i][1] ;
			var s = aXmlHttp[i][0].responseText ;
			aXmlHttp[i][0] = null ;
			aXmlHttp[i][1] = null ;
			aXmlHttp[i] = null ;
			f.apply( o, new Array( s ) ) ;
		}
	}
}

// u -> url
// o -> object (can be null) to invoke function on
// f -> callback function
// p -> optional argument to specify POST
function call( u, o, f ) {
	var method = "GET" ;
	var dat ;
	if ( arguments.length == 4 ) {
		method = "POST" ;
		tmp = u.split(/\?/) ;
		u = tmp[0] ;
		dat = tmp[1] ;
	}
	var idx = aXmlHttp.length;
	for( var i = 0; i < idx; i++ )
	if ( aXmlHttp[i] == null ) {
		idx = i ;
		break ;
	}
	aXmlHttp[idx] = new Array(2) ;
	aXmlHttp[idx][0] = getXMLHTTP() ;

	aXmlHttp[idx][1] = o ;
	aXmlHttp[idx][2] = f ;
	if( aXmlHttp[idx] ) {
		aXmlHttp[idx][0].open( method, u, true ) ;
		if( method == "POST" ) {
			aXmlHttp[idx][0].setRequestHeader("Content-Type", "application/x-www-form-urlencoded") ;
			aXmlHttp[idx][0].send( dat ) ;
		}
		aXmlHttp[idx][0].onreadystatechange = xmlResult ;
		if( method =="GET" ) {
			aXmlHttp[idx][0].send( null ) ;
		}
	}
}

function getXMLHTTP() {
	var A = null ;
	if( !A && typeof XMLHttpRequest != "undefined" ) {
		A = new XMLHttpRequest() ;
	}
	if ( !A ) {
		try {
			A = new ActiveXObject( "Msxml2.XMLHTTP" ) ;
		} catch( e ) {
			try {
				A = new ActiveXObject( "Microsoft.XMLHTTP" ) ;
			} catch( oc ) {
				A = null ;
			}
		}
	}
	return A ;
}

function screencenter(elem) {
	if (document.viewport) {
		var offsets = document.viewport.getScrollOffsets();
		var alert_size = $( elem ).getDimensions();
		var viewport_size = document.viewport.getDimensions();
		
		$( elem ).style.top = ( offsets.top + ( ( viewport_size.height / 2 ) - ( alert_size.height / 2 ) ) ) + 'px';
		$( elem ).style.left = ( ( viewport_size.width / 2 ) - ( alert_size.width / 2 ) ) + 'px';
	}
}

function showalert( val ) {
	document.getElementById( 'loadwindow' ).style.display = '' ;
	document.getElementById( 'loadwindow' ).innerHTML = val ;
	screencenter( 'loadwindow' );
	window.setTimeout( "hidealert()", 3000 ) ;
}

function hidealert() {
	document.getElementById( 'loadwindow' ).style.display = 'none' ;
}