function toggle(div_id) {
	var el = document.getElementById(div_id);
	if ( el.style.display == 'none' ) {	el.style.display = 'block';}
	else {el.style.display = 'none';}
}
function blanket_size(popUpDivVar) {	
	if( typeof( window.innerWidth ) == 'number' ) {
    //Non-IE
    blanket_width = window.innerWidth;
    blanket_height = window.innerHeight;
	} else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
    //IE 6+ in 'standards compliant mode'
    blanket_width = document.documentElement.clientWidth;
    blanket_height = document.documentElement.clientHeight;
	} else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
    //IE 4 compatible
    blanket_width = document.body.clientWidth;
    blanket_height = document.body.clientHeight;
	} 
	var blanket = document.getElementById('blanket');
	blanket.style.height = blanket_height + 'px';
	var popUpDiv = document.getElementById(popUpDivVar);
	popUpDiv_height=blanket_height/2-274;//150 is half popup's height
	popUpDiv.style.top = popUpDiv_height + 'px';
}
function window_pos(popUpDivVar) {
	if (typeof window.innerWidth != 'undefined') {
		viewportwidth = window.innerHeight;
	} else {
		viewportwidth = document.documentElement.clientHeight;
	}
	if ((viewportwidth > document.body.parentNode.scrollWidth) && (viewportwidth > document.body.parentNode.clientWidth)) {
		window_width = viewportwidth;
	} else {
		if (document.body.parentNode.clientWidth > document.body.parentNode.scrollWidth) {
			window_width = document.body.parentNode.clientWidth;
		} else {
			window_width = document.body.parentNode.scrollWidth;
		}
	}
	var popUpDiv = document.getElementById(popUpDivVar);
	window_width=window_width/2-320;//150 is half popup's width
	popUpDiv.style.left = window_width + 'px';
}
function popup(windowname) {
	blanket_size(windowname);
	window_pos(windowname);
	toggle('blanket');
	toggle(windowname);		
}