function toggleLayer( whichLayer )
{  
    var elem, vis;  

    if( document.getElementById ) // this is the way the standards work    
        elem = document.getElementById( whichLayer );  
    else if( document.all ) // this is the way old msie versions work      
        elem = document.all[whichLayer];  
    else if( document.layers ) // this is the way nn4 works    
        elem = document.layers[whichLayer];  
        
    vis = elem.style;    
        
    //vis.display = (vis.display==''||vis.display=='none') ? 'block' : 'none';
    if (vis.display == 'none')
    {
        vis.display = 'block';
    }
    else 
    {
        vis.display = 'none';
    }
      
    
}

/*
This function can be used in any validation since it takes the field name as a paramter.
Only checks to see if the field is blank.
*/
function validate_required(field)
{
    with (field)
    {
        if (value==null||value=="")
        {
            return false;
        }
        else {return true;}
    }
}

/*
Form validate script for addbook.aspx
*/
function validate_form_addbook()
{
    if(document.getElementById("<%=txtShortTitle.ClientID %>").value=="")
    {
        alert('fuck you');
        return false;
    }
    if(document.getElementById("<%=txtLongTitle.ClientID %>").value=="")
    {
        return false;
    }
    if(document.getElementById("<%=txtAuthor.ClientID %>").value=="")
    {
        return false;
    }
    if(document.getElementById("<%=txtYear.ClientID %>").value=="")
    {
        return false;
    }
    if(document.getElementById("<%=txtPlaceOfPub.ClientID %>").value=="")
    {
        return false;
    }
    if(document.getElementById("<%=txtPublisher.ClientID %>").value=="")
    {
        return false;
    }
    if(document.getElementById("<%=txtVolumes.ClientID %>").value=="")
    {
        return false;
    }
    if(document.getElementById("<%=txtLanguages.ClientID %>").value=="")
    {
        return false;
    }
    if(document.getElementById("<%=txtCollection.ClientID %>").value=="")
    {
        return false;
    }
    if(document.getElementById("<%=txtSubject.ClientID %>").value=="")
    {
        return false;
    }

    return true;
}