window.addEvent('domready', function(){
	center('apresentacao')
});

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;
    }

    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.getSize();

    var setX = ( my_width  - elementDimensions.size.x  ) / 2;
    var setY = ( my_height - elementDimensions.size.y ) / 2 + scrollY;

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

    element.style.left = setX + "px";
    element.style.top  = setY + "px";
}