function toggle_left()
{
    var x = document.getElementById('left_1_h');
    if (x.style.display == 'none')
    {
        x.style.display = '';
        x = document.getElementById('left_1_div');
        x.style.display = '';

        x = document.getElementById('left_2_h');
        x.style.display = 'none';
        x = document.getElementById('left_2_div');
        x.style.display = 'none';

    }
    else
        {
           x.style.display = 'none';
        x = document.getElementById('left_1_div');
        x.style.display = 'none';

        x = document.getElementById('left_2_h');
        x.style.display = '';
        x = document.getElementById('left_2_div');
        x.style.display = '';
        }
}
function toggle_right()
{
    var x = document.getElementById('right_1_h');
    if (x.style.display == 'none')
    {
        x.style.display = '';
        x = document.getElementById('right_1_div');
        x.style.display = '';

        x = document.getElementById('right_2_h');
        x.style.display = 'none';
        x = document.getElementById('right_2_div');
        x.style.display = 'none';

    }
    else
        {
           x.style.display = 'none';
        x = document.getElementById('right_1_div');
        x.style.display = 'none';

        x = document.getElementById('right_2_h');
        x.style.display = '';
        x = document.getElementById('right_2_div');
        x.style.display = '';
        }
}