var openitem;
var opencontainer;

function showhide( object1, object2 )
{
    if ( openitem ) {
        document.getElementById( openitem ).style.display = 'none';
        document.getElementById( opencontainer ).style.backgroundImage = 'url(_images/sect_plus.gif)';
    }
    
    if ( openitem != object1 ) {
        document.getElementById( object1 ).style.display = 'block';
        document.getElementById( object2 ).style.backgroundImage = 'url(_images/sect_minus.gif)';
        openitem = object1;
        opencontainer = object2;
    }
    else {
        document.getElementById( openitem ).style.display = 'none';
        openitem = null;
        document.getElementById( object2 ).style.backgroundImage = 'url(_images/sect_plus.gif)';
    }
}