function thisMovie (movieName) {    
/*
    if (navigator.appVersion.indexOf("MSIE 6.0") != -1) {
        // alert('IE6sucks');     
    }
*/
    if (navigator.appName.indexOf("Microsoft") != -1) {        
        return window[movieName];
    } else {
        return document[movieName];
    }
}

function enlargeDiv (arg)    {
    var obj = document.getElementById('mainnav');
    var p = thisMovie( 'menu_cos' );
    obj.style.height = arg + 'px';
    p.height = arg;
}

function minimizeDiv ()   {
	var obj = document.getElementById('mainnav');
	obj.style.height = '43' + 'px';
	var p = thisMovie( 'menu_cos' );
	p.height = '43px';
}