// PG Calculator JavaScript

var image_type = 0;

function changeState( request )
{
        if( request.readyState == 4 )
        {
                if( request.status == 200 )
                {
                        document.getElementById( "Display" ).innerHTML = request.responseText;
                }
        }
}

function visitCounter()
{
    var url = "./scripts/php/visitors.php";
	
    var request = new XMLHttpRequest();
    if( request )
    {
	//request.onreadystatechange = function handler() { changeState( request ); }
	request.open( "GET", url, false );
	request.send( null );
	if( request.readyState == 4 ) // status == 200 )
	{
	    document.getElementById( "VisitCounter" ).innerHTML = "Visits: " + request.responseText;
	}
	else
	{
	    document.getElementById( "VisitCounter" ).innerHTML = "...";
        }
    }
}

function reloadTab( tab )
{
    var content;
    var url = "./pages/" + tab + ".txt";
	
    var request = new XMLHttpRequest();
    if( request )
    {
	//request.onreadystatechange = function handler() { changeState( request ); }
	request.open( "GET", url, false );
	request.send( null );
	if( request.readyState == 4 ) // status == 200 )
	{
	    document.getElementById( "Display" ).innerHTML = request.responseText;
	}
	else
	{
	    document.getElementById( "Display" ).innerHTML = "The content will be available soon...";
        }
    }
    if( image_type )
    {
	reloadImage( 'pgcalc.gif' );
    }
}

function reloadImage( imageName )
{
    var imageUrl = "./images/" + imageName;
    document.getElementById( "Picture" ).src = imageUrl;
    image_type = ( imageName == 'pgcalc.gif' ? 0 : 1 );
    
    /*
    var request = new XMLHttpRequest();
    if( request )
    {
	//request.onreadystatechange = function handler() { changeState( request ); }
        request.open( "GET", imageUrl, false );
        request.send( null );
	if( request.readyState == 4 ) // status == 200 )
	{
	    document.getElementById( "Picture" ).src = request.responseText;
	}
	else
	{
	    document.getElementById( "Display" ).innerHTML = "The content will be available soon...";
	}
    } */   
}

function initPage()
{
    reloadTab( 'home' );
    reloadImage( 'pgcalc.gif' );
    visitCounter();
}