Question

The custom function formdvalidate should run after else but it doesn’t. How can I trigger it to run?
What I like to accomplish here is to check the text-fields of a form. If there are less then 3 characters its show the user some text. If the input is more then 3 it submits the form.

–I was thinking to wrong way, this works better.

$('#submit').click(formdvalidate);

The function

function formdvalidate(){
    $(".form-sel").each(function(){
        var n = $(this).closest('.contain-form').find('.custom:first').val().length;
        if ($('option:selected', this).val() === 'custom' && n < 3) {
            $(this).closest('.contain-form').find('.alert-short:first').show();
        }else{                          
            $('#poll').submit();
        }
    });                 
}

Answer 1

1. A function assigned as a click handler via .click() takes a jQuery event object as its first param–you named that param the same as your function
2. formdvalidate === true will never evaluate to true as formdvalidate is a function in the global scope, and a jQuery event object in the click() scope as per item 1
3. In your formdvalidate function, your return is inside of the .each() function, so formdvalidate never actually returns anything.

I’m not sure what you’re really after or what your page looks like, but based on your comment to Slava Yanson, my best guess for you is below (although there are still things I am unsure of…)

$( '#submit' ).click( function( e )
{
  if( formdvalidate() === true) 
  {
    $( '#poll' ).submit();
  }

  e.preventDefault();
} );

function formdvalidate()
{
  var returnValue;

  $( '.form-sel' ).each( function()
  {
    var $containForm = $( this ).closest( '.contain-form' ),
        $alertShortFirst = $containForm.find( '.alert-short:first' ),
        n = $containForm.find( '.custom:first' ).val().length;
    if( $( 'option:selected', this ).val() === 'custom' && n < 3 )
    {
      $alertShortFirst.show();
      returnValue = false;
    }
    else
    {
      $alertShortFirst.hide();
      returnValue = true;
    }
  } );

  return returnValue;
}