too add a placeholder in select2 i have to add an empty option tag in the code like this

<select id="e2" name="rol_id" >

                       <option><option>

                       {foreach from=$data.roles item=rol}

                       <option value={$rol.rol_id}>{$rol.rol_nombre}</option>

                       {/foreach}

 </select>

but when i do that i get this option empty that is selectable

how can i not show that option but still the placeholder?

Thanks!