jQuery(document).ready(function(){
    var elements    = [
        jQuery('#elem_purpose'), 
        jQuery('#elem_name'),         
        jQuery('#elem_sub'), 
        jQuery('#elem_bg'),
        jQuery('#elem_pos'),
        jQuery('#elem_size'),
        jQuery('#elem_activity'),
        jQuery('#elem_extension')
    ],
        picNameContainer = jQuery('#pic_name'),
        separator        = jQuery('#elem_separator');
    picNameContainer.css({ fontSize : '20px', color : '#2870DD' });
    jQuery('#calculate_name').bind('click', function(){
        var picName = '';
        jQuery.each(elements, function( n, elem){
            var val = elem.val();
            picName += ( ( n == 1 ) && ( val != '') )? '_' + val : val;
        });
        if ( separator.val() == '-' ) picName = picName.split('_').join('-');
        picNameContainer.text( picName );
    });
        
});