Create date-validation.md

erpnext/docs/user/manual/de/customize-erpnext/custom-scripts/custom-script-examples/date-validation.md

@@ -0,0 +1,10 @@
+## 15.3.1.2 Datenvalidierung
+
+frappe.ui.form.on("Event", "validate", function(frm) {
+    if (frm.doc.from_date < get_today()) {
+        msgprint(__("You can not select past date in From Date"));
+        throw "past date selected"
+    }
+});
+
+{next}