var deltaX, deltaY, windowWidth, windowHeight, imgWidth, imgHeight;

function move(objName, dx, dy, speed){
	obj = document.getElementById(objName);
	obj_img = document.getElementById(objName+"_img");
	deltaX = dx;
	deltaY = dy;
	imgWidth = obj_img.width;
	imgHeight = obj_img.height;
	newSize();
	
//	fly(obj);
	setInterval('fly(obj)', speed);
}

function newSize(){
	if(window.innerWidth){
		windowWidth = window.innerWidth - imgWidth - 1;
		windowHeight = window.innerHeight - imgHeight - 1;
	}
	else{
		windowWidth = document.body.offsetWidth - imgWidth - 1;
		windowHeight = document.body.offsetHeight - imgHeight - 1;
	}
}

function fly(obj){
	xPos = eval(obj.style.left.replace(/p./, ""));
	yPos = eval(obj.style.top.replace(/p./, ""));
	
	xPos = xPos + deltaX;
	yPos = yPos + deltaY;
	
	if(xPos < 0){
		deltaX = Math.abs(deltaX);
	}
	if(xPos > windowWidth){
		deltaX = -Math.abs(deltaX);
	}
	if(yPos < 0){
		deltaY = Math.abs(deltaY);
	}
	if(yPos > windowHeight){
		deltaY = -Math.abs(deltaY);
	}
	xPos = xPos + "px";
	yPos = yPos + "px";
	
	obj.style.left = xPos;
	obj.style.top = yPos;
}

function show(sObjName){
	sobj = document.getElementById(sObjName);
	sobj.style.visibility = "visible";
}