diff --git a/addons/website_crm_partner_assign/static/src/js/crm_partner_assign.js b/addons/website_crm_partner_assign/static/src/js/crm_partner_assign.js
index e082fa155fd..2f94c8827ba 100644
--- a/addons/website_crm_partner_assign/static/src/js/crm_partner_assign.js
+++ b/addons/website_crm_partner_assign/static/src/js/crm_partner_assign.js
@@ -226,7 +226,9 @@ sAnimations.registry.crmPartnerAssign = sAnimations.Class.extend({
     _onEditOppConfirm: function (ev) {
         ev.preventDefault();
         ev.stopPropagation();
-        this._buttonExec($(ev.currentTarget), this._editOpportunity);
+        if ($(".edit_opp_form")[0].checkValidity()) {
+            this._buttonExec($(ev.currentTarget), this._editOpportunity);
+        }
     },
     /**
      * @private
diff --git a/addons/website_crm_partner_assign/views/website_crm_partner_assign_templates.xml b/addons/website_crm_partner_assign/views/website_crm_partner_assign_templates.xml
index 70ff4d891af..9e060b8d04e 100644
--- a/addons/website_crm_partner_assign/views/website_crm_partner_assign_templates.xml
+++ b/addons/website_crm_partner_assign/views/website_crm_partner_assign_templates.xml
@@ -670,7 +670,7 @@
                                                     <div class="col-md-6">
                                                         <label>Expected Closing:</label>
                                                         <div class="input-group date">
-                                                            <input type="text" name="date_deadline" t-att-value="opportunity.date_deadline" class="form-control date_deadline" data-date-format="YYYY-MM-DD" t-att-name="prefix" placeholder="YYYY-MM-DD"/>
+                                                            <input type="date" min="1900-01-01" name="date_deadline" t-att-value="opportunity.date_deadline" class="form-control date_deadline" data-date-format="YYYY-MM-DD" t-att-name="prefix" placeholder="YYYY-MM-DD"/>
                                                             <div class="input-group-append">
                                                                 <span class="input-group-text">
                                                                     <span class="fa fa-calendar" role="img" aria-label="Calendar"></span>
@@ -695,7 +695,7 @@
                                             <div class="form-group">
                                                 <label class="col-form-label" for="activity_date_deadline">Next Activity Date</label>
                                                 <div class="input-group date">
-                                                    <input type="text" name="activity_date_deadline" t-att-value="user_activity.date_deadline" class="form-control activity_date_deadline" data-date-format="YYYY-MM-DD" t-att-name="prefix" placeholder="YYYY-MM-DD"/>
+                                                    <input type="date" min="1900-01-01" name="activity_date_deadline" t-att-value="user_activity.date_deadline" class="form-control activity_date_deadline" data-date-format="YYYY-MM-DD" t-att-name="prefix" placeholder="YYYY-MM-DD"/>
                                                     <div class="input-group-append">
                                                         <span class="input-group-text">
                                                             <span class="fa fa-calendar" role="img" aria-label="Calendar" title="Calendar"></span>