diff --git a/includes/form.inc b/includes/form.inc
index baadcef..4635cf2 100644
--- a/includes/form.inc
+++ b/includes/form.inc
@@ -3911,6 +3911,11 @@ function theme_button($variables) {
   $element['#attributes']['type'] = 'submit';
   element_set_attributes($element, array('id', 'name', 'value'));
 
+  // Remove name attribute if empty, for W3C compliance.
+  if (isset($element['#attributes']['name']) && $element['#attributes']['name'] === '') {
+    unset($element['#attributes']['name']);
+  }
+
   $element['#attributes']['class'][] = 'form-' . $element['#button_type'];
   if (!empty($element['#attributes']['disabled'])) {
     $element['#attributes']['class'][] = 'form-button-disabled';
diff --git a/modules/search/search.test b/modules/search/search.test
index 913d198..2d34200 100644
--- a/modules/search/search.test
+++ b/modules/search/search.test
@@ -630,6 +630,12 @@ class SearchBlockTestCase extends DrupalWebTestCase {
     $edit = array('blocks[search_form][region]' => 'content');
     $this->drupalPost('admin/structure/block', $edit, t('Save blocks'));
 
+    // Check that name attribute is not empty.
+    $this->drupalGet('');
+    $pattern = "//input[@type='submit' and @name='']";
+    $elements = $this->xpath($pattern);
+    $this->assertTrue(empty($elements), 'The search input field does not have empty name attribute.');
+
     // Test a normal search via the block form, from the front page.
     $terms = array('search_block_form' => 'test');
     $this->drupalPost('node', $terms, t('Search'));