function validateMaximum(e, max, receptor)
{
    txt = e.value
    length = e.value.length
    free = max - length
    if ( free >= 0 )
    {
        document.getElementById(receptor).innerHTML = String(free)
    }
    e.value = txt.substring(0, max)
}


function fieldIdentifyer()
{
    e = document.activeElement

    switch(e.id)
    {
        case 'wall_comment':
            validateMaximum(e, 300, 'num_carac_wall')
            break;
        case 'editprofile_description':
            validateMaximum(e, 600, 'num_carac_aboutme')
            break;
        case 'sendvideo_description':
            validateMaximum(e, 200, 'num_carac_editprofile_description')
            break;
    }
}


window.onkeyup = fieldIdentifyer