function wechsel(wert, id, baseURL) 
{ 
    var obj = document.getElementById(wert);
    
    if (obj.style.display == 'block')
    {
        obj.style.display = 'none';
        
        obj = document.getElementById(id);
        obj.src= baseURL + "img/play.png"
    } 
    else 
    {
        obj.style.display = 'block';
        
        obj = document.getElementById(id);
        obj.src=baseURL + "img/play_2.png"
    }
    
    return;

}