function switchBackground(elementid)
{  
    var container = document.getElementById(elementid);
    if (container != null){
       /* alert(container.offsetHeight); */
        if (container.offsetHeight <= 150 ){
            container.style.height = '150px';
            container.style.background = 'url(/images/bg_height_150.jpg) no-repeat left top';     
        }else if (container.offsetHeight <= 299 ){
            container.style.height  = '300px';
            container.style.background = 'url(/images/bg_height_300.jpg) no-repeat left top';     
        }else if (container.offsetHeight <= 499 ){
            container.style.height  = '500px';
            container.style.background = 'url(/images/bg_height_500.jpg) no-repeat left top';    
        }else if (container.offsetHeight <= 699 ){
            container.style.height = '700px';
            container.style.background = 'url(/images/bg_height_700.jpg) no-repeat left top';  
        }else if (container.offsetHeight <= 899 ){
            container.style.height = '900px';
            container.style.background = 'url(/images/bg_height_900.jpg) no-repeat left top'; 
        }else if (container.offsetHeight <= 1099 ){
            container.style.height = '1100px';
            container.style.background = 'url(/images/bg_height_1100.jpg) no-repeat left top'; 
        }else if (container.offsetHeight <= 1299 ){
            container.style.height = '1300px';
            container.style.background = 'url(/images/bg_height_1300.jpg) no-repeat left top'; 
        }else if (container.offsetHeight <= 2029 ){
            container.style.height = '2030px';
            container.style.background = 'url(/images/bg_height_2030.jpg) no-repeat left top'; 
         }else if (container.offsetHeight <= 2229 ){
            container.style.height = '2230px';
            container.style.background = 'url(/images/bg_height_2230.jpg) no-repeat left top';
        }else if (container.offsetHeight <= 2429 ){
            container.style.height = '2430px';
            container.style.background = 'url(/images/bg_height_2430.jpg) no-repeat left top';
        }else if (container.offsetHeight <= 2829 ){
            container.style.height = '2830px';
            container.style.background = 'url(/images/bg_height_2830.jpg) no-repeat left top';
        }else if (container.offsetHeight > 2829 ){
            container.style.background = 'url(/images/bg_height_2830.jpg) no-repeat left top';  
        } 
    }                                               
    
}