img1 = new Image;
img1.src = "images/pageView_a.gif";
img2 = new Image;
img2.src = "images/nav_arrowL_a.gif";
img3 = new Image;
img3.src = "images/nav_arrowR_a.gif";
img4 = new Image;
img4.src = "";
//
siteWindow = 0;

function imgRoll(state, which,img){
	if(state==1){
		rollState = "a";
	}else{
		rollState = "i";
	}
	document.getElementById(which).src = "images/"+img+"_"+rollState+".gif";
}

// Open pop-up window with specified parameters
function centerScreen(URL, sizeX, sizeY, scrolls,name) {
	
	if(sizeX == "" || sizeY == ""){
		x=800;y=600;
	} else {
	  x=sizeX;y=sizeY;
	}
	if (scrolls == 1){
		scroller = "yes"
	}else{
		scroller = "no"
	}
	if(name!=null){
		nameVal = name;
	}else{
		nameVal = "popWin"
	}
	winLeft=eval(screen.availWidth/2)-(x/2);
	winTop=eval(screen.availHeight/2)-(y/2);
  siteWindow = window.open
	(URL,nameVal,"width="+x+",height="+y+",toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars="+scroller+",resizable=yes,left="+winLeft+",top="+winTop);
}