问题
Drupal automatically adds <div>'s and classes around form items. All form elements will have the attribute class = "form-item". How do I override this default behavior?
回答1:
If you insist on changing it, it's added in the theme_form_element function. You can override it by copying that function to your theme's template.php file and renaming it THEMENAME_form_element (substituting the name of your theme in place of "THEMENAME") or phptemplate_form_element and removing the part that adds the class.
回答2:
In real experience these are useful classes, but if you want to extremely clear form you can theme each form element or theme form:
Much closer to your task i found here (not only zen theme and not only for user login block): Custom User Login Block on Drupal 6 Zen sub-themes in "Advanced theming" part, see bottom code.
来源：https://stackoverflow.com/questions/5012870/remove-class-form-item-from-drupal-forms