function getViewportDimensions() {
    var intH = 0, intW = 0;
    
    if(self.innerHeight) {
       intH = window.innerHeight;
       intW = window.innerWidth;
    } 
    else {
        if(document.documentElement && document.documentElement.clientHeight) {
            intH = document.documentElement.clientHeight;
            intW = document.documentElement.clientWidth;
        }
        else {
            if(document.body) {
                intH = document.body.clientHeight;
                intW = document.body.clientWidth;
            }
        }
    }

    return {
        height: parseInt(intH, 10),
        width: parseInt(intW, 10)
    };
}

function centerElement(elem) {
    var viewport = getViewportDimensions();
    var left = (viewport.width == 0) ? 50 : parseInt((viewport.width - 807) / 2, 10);

    elem.style.left = left + 'px';

    viewport, left, elem = null;    
}

function centerOtherElement(elem) {
    var viewport = getViewportDimensions();
    var left = (viewport.width == 0) ? 50 : parseInt((viewport.width - 700) / 2, 10);

    elem.style.left = left + 'px';

    viewport, left, elem = null;    
}

function centerLastElement(elem) {
    var viewport = getViewportDimensions();
    var left = (viewport.width == 0) ? 50 : parseInt((viewport.width - 600) / 2, 10);

    elem.style.left = left + 'px';

    viewport, left, elem = null;    
}