I would like to know How can you get the amount of divs, in this case from the div_principal class, which are not included in the class div_global? In this case you should return value.
<div class="div_global">
<div class="div_principal"></div>
<div class="div_principal"></div>
<div class="div_principal"></div>
</div>
<div class="div_principal"></div>
<div class="div_principal"></div>