diff --git a/templates/create_certificate.html b/templates/create_certificate.html
index eaec94a..2a2d9d2 100644
--- a/templates/create_certificate.html
+++ b/templates/create_certificate.html
@@ -58,7 +58,11 @@
             <div class="row mb-3">
                 <div class="col-md-6">
                     <label for="san_dns" class="form-label">SAN DNS (可选)</label>
-                    <input type="text" class="form-control" id="san_dns" name="san_dns">
+                    <input type="text" class="form-control" id="common_name" name="common_name"
+                           pattern="[a-zA-Z0-9.-]+"
+                           title="只能包含字母、数字、点号和短横线，且不能以点号或短横线开头或结尾">
+                           pattern="[a-zA-Z0-9.-]+"
+                           title="只能包含字母、数字、点号和短横线，且不能以点号或短横线开头或结尾">
                     <div class="form-text">多个DNS用逗号分隔，如: example.com,www.example.com</div>
                 </div>
                 <div class="col-md-6">