diff --git a/setup.cfg b/setup.cfg
index 9780042..4020402 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,6 +1,6 @@
 [metadata]
 name = yamlhttpforms
-version = 0.0.4
+version = 0.0.5
 author = Daniil F.
 author_email = mail@placeholder123.to
 description = HTTP forms defined in YAML
diff --git a/src/yamlhttpforms/html.py b/src/yamlhttpforms/html.py
index 37610f7..70463a3 100644
--- a/src/yamlhttpforms/html.py
+++ b/src/yamlhttpforms/html.py
@@ -1,4 +1,6 @@
+import sys
 from typing import Dict, TYPE_CHECKING
+
 from bs4.element import Tag
 
 if TYPE_CHECKING:
@@ -8,6 +10,8 @@ if TYPE_CHECKING:
 INPUT, SELECT, OPTION = 'input', 'select', 'option'
 NAME, VALUE, SELECTED = 'name', 'value', 'selected'
 
+NON_PRINTABLE_TO_NONE = {code: None for code in range(sys.maxunicode + 1) if not chr(code).isprintable()}
+
 
 class WrongInterface(Exception):
     pass
@@ -29,6 +33,10 @@ class UnknownField(WrongInterface):
     pass
 
 
+def printable_only(string: str) -> str:
+    return string.translate(NON_PRINTABLE_TO_NONE)
+
+
 def check_select_field_options(field_tag: Tag, field_interface: 'FormField', check_defaults: bool = True) -> None:
     """
     Compares the `options` and `default` attributes of a `'FormField'` object with the options of its HTML counterpart.
@@ -45,7 +53,7 @@ def check_select_field_options(field_tag: Tag, field_interface: 'FormField', che
         `FieldInterfaceWrong`
             if the `default` is not equal to the value of the <option> tag which has the `selected` attribute
     """
-    html_options = {(tag[VALUE], tag.get_text(strip=True)) for tag in field_tag.find_all(OPTION)}
+    html_options = {(tag[VALUE], printable_only(tag.get_text(strip=True))) for tag in field_tag.find_all(OPTION)}
     interface_options = set(field_interface.options.items())
     missing_in_interface = html_options - interface_options
     not_in_html = interface_options - html_options
@@ -59,9 +67,9 @@ def check_select_field_options(field_tag: Tag, field_interface: 'FormField', che
     if s:
         raise SelectOptionsWrong(f"Wrong options in field '{field_interface.name}'." + s)
     if check_defaults:
-        default = field_tag.find(lambda tag: tag.name == OPTION and tag.has_attr(SELECTED))[VALUE]
-        if default != field_interface.default:
-            raise FieldInterfaceWrong(f"Default option '{default}' missing for {field_interface}")
+        default_option = field_tag.find(lambda tag: tag.name == OPTION and tag.has_attr(SELECTED))
+        if default_option is not None and default_option[VALUE] != field_interface.default:
+            raise FieldInterfaceWrong(f"Default option '{default_option[VALUE]}' missing for {field_interface}")
 
 
 def check_field_interface(field_tag: Tag, field_interface: 'FormField', check_defaults: bool = True) -> None:
@@ -109,7 +117,7 @@ def check_form_interface(form_tag: Tag, form_interface: 'Form', check_defaults:
     """
     field_tags: Dict[str, Tag] = {tag[NAME]: tag for tag in form_tag.find_all(INPUT) + form_tag.find_all(SELECT)}
     for field in form_interface.fields.values():
-        tag = field_tags.pop(field.name)
+        tag = field_tags.pop(field.name, None)
         if tag is None:
             raise UnknownField(f"The defined field does not exist in the form: {field}")
         check_field_interface(tag, field, check_defaults=check_defaults)