public static function print_user_split_field()
{
$field_name = 'user_split';
printf('<select id="%1$s" name="nelioab_settings[%1$s]" %2$s>', $field_name, self::get_basic_details());
?>
<?php
$val = NelioABSettings::USER_SPLIT;
?>
<option value='<?php
echo $val;
?>
'><?php
_e('Group Experiments and Divide Visitors', 'nelioab');
?>
</option>
?></option>
<?php
$val = NelioABSettings::USER_ALLIN;
?>
<option value='<?php
echo $val;
?>
'<?php
if (NelioABSettings::get_split_user_mode() == $val) {
echo ' selected="selected"';
}
?>
><?php
_e('Test All Experiments with All Visitors', 'nelioab');
?>
</option>
</select>
<div class="the-descr" style="display:none;"><span class="description"><?php
printf(__('When running more than one experiment with multiple alternatives each one, the total number of combinations grows exponentially, which may degrade your server\'s performance. To overcome this issue, enable the option «Group Experiments and Divide Visitors». If enabled, the plugin creates one or more experiment groups, each of which will test a few experiments only. When a visitor accesses your website, she only participates in the experiments of one of the available groups. <a%s>Read More</a>', 'nelioab'), ' href="http://support.nelioabtesting.com/solution/articles/1000167944" target="_blank"');
?>
</span></div><?php
}