diff --git a/include/class.forms.php b/include/class.forms.php
index 3fadfd17822e0276fa54045f807afe3ceef3d4a2..c6b2fc7b0795a80afd2000a867c02e9e948724d4 100644
--- a/include/class.forms.php
+++ b/include/class.forms.php
@@ -1441,6 +1441,8 @@ class TextboxField extends FormField {
     }
 
     function validateEntry($value) {
+        //check to see if value is the string '0'
+        $value = ($value == '0') ? '&#48' : Format::htmlchars($this->toString($value ?: $this->value));
         parent::validateEntry($value);
         $config = $this->getConfiguration();
         $validators = array(