function showBox(){
    $('overlay').show();
    center('box');
	
    return false;
}

function hideBox(){
    $('box').hide();
    $('overlay').hide();
	
    return false;
}

function center(element) {
    try {
		element	= $(element);
    } catch(e) {
        return;
    }

    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;
    }

    element.style.position	= 'absolute';
    element.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	= Element.getDimensions(element);
    var setX				= (my_width - elementDimensions.width) / 2;
    var setY				= (my_height - elementDimensions.height) / 2 + scrollY;

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

    element.style.left	= (setX-150) + "px";
    element.style.top	= (setY-100) + "px";
    element.style.display  = 'block';
}