search_filterOnFocus = function( search_filter )
{
    if (search_filter.value == 'Zoeken...')
    {
        search_filter.value = ''
    }    
}
search_filterOnBlur = function( search_filter )
{
    if ((search_filter.value).replace(/^\s+|\s+$/g, '') == '')
    {
        search_filter.value = 'Zoeken...'
    }
}