var imgs;
var changeSpeed = 5000;

// the window.onload is overridden by a body onload only in PropertyDetail page,
// so the initPromo needs to be called from body onload there
window.onload = function() {
	try {
		initPromo(); 
	}
	catch(e) {
	}
}; 

function initPromo() {
    imgs = document.getElementById('header-img').getElementsByTagName('img');
	if(imgs.length > 1) {
		for(var i=1; i<imgs.length; i++) {
			imgs[i].style.display = "none";
		}
	    setTimeout("runPromo(" + 1 + ", " + imgs.length + ")", changeSpeed);
	}
}  

function runPromo(imgNo, length) {
	try {
		if(imgNo < length) {
			_opacity("header-img", 100, 0, 500);
			
			setTimeout("runEach(" + imgNo + ")", 500);
		}
		
		if(imgNo < length - 1) {
			setTimeout("runPromo(" + (imgNo + 1) + ", " + length + ")", changeSpeed);
		}
		else {
			setTimeout("runPromo(0, " + length + ")", changeSpeed);
		}
	}
	catch(e) {
	}
}

function runEach(imgNo) {
	try {
	    if(imgNo > 0)
	        imgs[imgNo - 1].style.display = "none";
	    else
	        imgs[imgs.length - 1].style.display = "none";
	        
		//document.getElementById("header").innerHTML = "<img src='" + imgSrc + "' alt='' />";
		imgs[imgNo].style.display = "";
		
		_opacity("header-img", 0, 100, 500);
	}
	catch(e) {
	}
}

function _opacity(id, opacStart, opacEnd, millisec) {
    // speed for each frame
    var speed = Math.round(millisec / 100);
    var timer = 0;
    
    // determine the direction for the blending,
	// if start and end are the same nothing happens
    if(opacStart > opacEnd) {
        for(i = opacStart; i >= opacEnd; i--) {
            setTimeout("changeOpac(" + i + ", '" + id + "', 'down')", (timer * speed));
            timer++;
        }
    }
    else if(opacStart < opacEnd) {
        for(i = opacStart; i <= opacEnd; i++) {
            setTimeout("changeOpac(" + i + ", '" + id + "', 'up')", (timer * speed));
            timer++;
        }
    }
}

function changeOpac(opacity, id, dir) {
    var object = document.getElementById(id).style;
    object.opacity = (opacity / 100);
    object.MozOpacity = (opacity / 100);
    object.KhtmlOpacity = (opacity / 100);
    object.filter = "alpha(opacity=" + opacity + ")";
    
    //when going to zero
    if(opacity == 0) {
		if(dir == "down") {
		}
		
		if(dir == "up") {
		}
	}
}