//get browser height
function getBrowserHeight() {
   var myHeight;
   if( typeof( window.innerWidth ) == 'number' ) { myHeight = window.innerHeight; }
   else if( document.documentElement && ( document.documentElement.clientWidth ||document.documentElement.clientHeight ) ) { myHeight = document.documentElement.clientHeight; }
   else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) { myHeight = document.body.clientHeight; }
   return myHeight;
}

//set container vertical position
function boxHeight() {
   var cenvertpage	= ( parseInt( getBrowserHeight() ) / 2 );
   var cenvertbox		= ( parseInt( document.getElementById( 'wrapper' ).offsetHeight ) / 2 );
   var cenverted		= cenvertpage - cenvertbox;
   if( cenverted < 0 ) {  document.getElementById( 'wrapper' ).style.top = 0 + 'px'; }
   else { document.getElementById( 'wrapper' ).style.top = cenverted + 'px'; }
   //alert(centvertpage);
}

//delay container display - eliminates visual 'bouncing' glitch
function delayBox() { document.getElementById( 'wrapper' ).style.visibility = 'visible'; }

//page-resize container
//get container height and center vertically on page
function resizeBox() { boxHeight(); }

//page-load container
var display;
function loadBox() {
   boxHeight();
   if( document.getElementById( 'wrapper' ).style.visibility != 'visible' ) { display = setTimeout( "delayBox()", 10 ); }
}

//placement onResize();
window.onresize = resizeBox;

//clear display timeout();
clearTimeout(display);