function showBox(){

	var o = null;

	if(document.all) { o = document.all("overlay"); }
	else if(document.getElementById) { o = document.getElementById("overlay"); }

	if(o!=null && o.style) {
		o.style.display = "block";
	}

	center('box');
	return false;
}

function hideBox(){

	var o1 = null;
	var o2 = null;

	if(document.all) {
		o1 = document.all("box");
		o2 = document.all("overlay");
	}
	else if(document.getElementById) {
		o1 = document.getElementById("box");
		o2 = document.getElementById("overlay");
	}

	if(o1!=null && o1.style && o2!=null && o2.style) {
		o1.style.display = "none";
		o2.style.display = "none";
	}

    return false;
}

function center(element){

	var o = null;

	if(document.all) { o = document.all(element); }
	else if(document.getElementById) { o = document.getElementById(element); }


    var my_width  = 0;
    var my_height = 0;

    if ( typeof( window.innerWidth ) == 'number' ){
        my_width  = window.innerWidth;
        my_height = window.innerHeight;
    }else if ( document.documentElement && 
             ( document.documentElement.clientWidth ||
               document.documentElement.clientHeight ) ){
        my_width  = document.documentElement.clientWidth;
        my_height = document.documentElement.clientHeight;
    }
    else if ( document.body &&
            ( document.body.clientWidth || document.body.clientHeight ) ){
        my_width  = document.body.clientWidth;
        my_height = document.body.clientHeight;
    }

    o.style.position = 'absolute';
    o.style.zIndex   = 99;

    var scrollY = 0;

    if ( document.documentElement && document.documentElement.scrollTop ){
        scrollY = document.documentElement.scrollTop;
    }else if ( document.body && document.body.scrollTop ){
        scrollY = document.body.scrollTop;
    }else if ( window.pageYOffset ){
        scrollY = window.pageYOffset;
    }else if ( window.scrollY ){
        scrollY = window.scrollY;
    }

    var elementDimensions = getDimensions(element);

    var setX = ( my_width  - elementDimensions[0]  ) / 2;
    var setY = ( my_height - elementDimensions[1] ) / 2 + scrollY;

    setX = ( setX < 0 ) ? 0 : setX;
    setY = ( setY < 0 ) ? 0 : setY;

    o.style.left = setX + "px";
    o.style.top  = setY + "px";

    o.style.display  = 'block';
}


function getDimensions(element) {

	var dimensionArr = new Array;

	var o = null;

	if(document.all) { o = document.all(element); }
	else if(document.getElementById) { o = document.getElementById(element); }


	if (o.style.display!='none') {
		dimensionArr[0] = o.offsetWidth;
		dimensionArr[1] = o.offsetHeight;
		return dimensionArr;
	}

	// All *Width and *Height properties give 0 on elements with display none,
	// so enable the element temporarily
	var els = o.style;
	var originalVisibility = els.visibility;
	var originalPosition = els.position;
	els.visibility = 'hidden';
	els.position = 'absolute';
	els.display = '';
	var originalWidth = o.clientWidth;
	var originalHeight = o.clientHeight;
	els.display = 'none';
	els.position = originalPosition;
	els.visibility = originalVisibility;

	dimensionArr[0] = originalWidth;
	dimensionArr[1] = originalHeight;
	return dimensionArr;
  }