maxlength depending on nodetype (contenttype) i use one field in different content-types. for example in article, this field should be limited to 130 characters, but in gallery, the same field should be limited to 50 characters. The field is also used to generate the breadcrumb menu, so i can not simply add another field. so is it possible, to set different maxlength-values depending on the nodetype?
You could use hook_node_presave to set the maximum length of a fields value before the node is saved or inserted in the database.

For example, to force a field field_dummy for a node of type article to a maximum of 50 characters you could do like this:

function HOOK_node_presave($node){
  if($node-&gt;type == 'article'):
    // force the field to max 50 characters
    $node-&gt;field_dummy[$node-&gt;language][0]['value'] = 
       substr($node-&gt;field_dummy[$node-&gt;language][0]['value'], 0, 50);
  endif;
}