diff --git a/ippisite/ippidb/forms.py b/ippisite/ippidb/forms.py
index 8aabad3a6b01c67da2eb04e71c84847dd73be93c..35e35581ff2815478e57e133ee20f36a18b6b60b 100644
--- a/ippisite/ippidb/forms.py
+++ b/ippisite/ippidb/forms.py
@@ -32,7 +32,7 @@ def validate_pdb_exists(value):
         raise ValidationError('PDB entry not found: %(value)s', params={'value': value}, code='invalid')
 
 class PDBForm(forms.Form):
-    pdb_id = forms.CharField(label="PDB ID",max_length=4, widget=forms.TextInput(attrs={'placeholder': 'e.g 4HHB'}), required=True, validators=[
+    pdb_id = forms.CharField(label="PDB ID",max_length=4, widget=forms.TextInput(attrs={'placeholder': 'e.g 4HHB', 'required':'required'}), required=True, validators=[
                 RegexValidator('^[0-9][a-zA-Z0-9]{3}$', message='PDB ID must be 1 numeric + 3 alphanumeric characters'),
                 validate_pdb_exists
              ])