diff --git a/serp.py b/serp.py
index f71038c..f871e6d 100644
--- a/serp.py
+++ b/serp.py
@@ -1695,7 +1695,7 @@ CRAWL_HTML = """
             </div>
             <div class="form-group">
                 <label>{{depth}}</label>
-                <input type="number" id="depth" value="9" min="1" max="15">
+                <input type="number" id="depth" value="9" min="-1" max="15">
             </div>
             <div class="form-group">
                 <label>{{max_pages}}</label>