diff --git a/isvalid_test.go b/isvalid_test.go
new file mode 100644
index 0000000..d61841c
--- /dev/null
+++ b/isvalid_test.go
@@ -0,0 +1,37 @@
+package mxj
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestXmlCheckIsValid(t *testing.T) {
+	fmt.Println("================== TestXmlCheckIsValid")
+
+	data := []byte(`{"":"empty", "$invalid":"hex$", "entities":"<>&", "nil": null}`)
+	m, err := NewMapJson(data)
+	if err != nil {
+		t.Fatal("NewMapJson err;", err)
+	}
+	fmt.Printf("%v\n", m)
+
+	XmlCheckIsValid()
+	defer XmlCheckIsValid()
+	if _, err = m.Xml(); err == nil {
+		t.Fatal("Xml err: nil")
+	}
+
+	if _, err = m.XmlIndent("", "   "); err == nil {
+		t.Fatal("XmlIndent err: nil")
+	}
+
+	ms, err := NewMapXmlSeq([]byte(`<doc><elem>element</elem></doc>`))
+	fmt.Printf("%v\n", ms)
+	if _, err = ms.Xml(); err != nil {
+		t.Fatal("Xml err:", err)
+	}
+
+	if _, err = ms.XmlIndent("", "   "); err != nil {
+		t.Fatal("XmlIndent err:", err)
+	}
+}
diff --git a/xml.go b/xml.go
index a551186..04788fd 100644
--- a/xml.go
+++ b/xml.go
@@ -694,8 +694,15 @@ func (mv Map) Xml(rootTag ...string) ([]byte, error) {
 	}
 done:
 	if xmlCheckIsValid {
-		if _, err = NewMapXml(b.Bytes()); err != nil {
-			return nil, err
+		d := xml.NewDecoder(bytes.NewReader(b.Bytes()))
+		for _, err = d.Token(); err != io.EOF; {
+			_, err = d.Token()
+			if err == io.EOF {
+				err = nil
+				break
+			} else if err != nil {
+				return nil, err
+			}
 		}
 	}
 	return b.Bytes(), err
@@ -937,8 +944,15 @@ func (mv Map) XmlIndent(prefix, indent string, rootTag ...string) ([]byte, error
 		err = marshalMapToXmlIndent(true, b, DefaultRootTag, m, p)
 	}
 	if xmlCheckIsValid {
-		if _, err = NewMapXml(b.Bytes()); err != nil {
-			return nil, err
+		d := xml.NewDecoder(bytes.NewReader(b.Bytes()))
+		for _, err = d.Token(); err != io.EOF; {
+			_, err = d.Token()
+			if err == io.EOF {
+				err = nil
+				break
+			} else if err != nil {
+				return nil, err
+			}
 		}
 	}
 	return b.Bytes(), err
diff --git a/xmlseq.go b/xmlseq.go
index 6427d0f..3fb90b8 100644
--- a/xmlseq.go
+++ b/xmlseq.go
@@ -448,8 +448,15 @@ func (mv MapSeq) Xml(rootTag ...string) ([]byte, error) {
 	}
 done:
 	if xmlCheckIsValid {
-		if _, err = NewMapXml([]byte(*s)); err != nil {
-			return nil, err
+		d := xml.NewDecoder(bytes.NewReader([]byte(*s)))
+		for _, err = d.Token(); err != io.EOF; {
+			_, err = d.Token()
+			if err == io.EOF {
+				err = nil
+				break
+			} else if err != nil {
+				return nil, err
+			}
 		}
 	}
 	return []byte(*s), err
@@ -544,6 +551,16 @@ func (mv MapSeq) XmlIndent(prefix, indent string, rootTag ...string) ([]byte, er
 		if _, err = NewMapXml([]byte(*s)); err != nil {
 			return nil, err
 		}
+		d := xml.NewDecoder(bytes.NewReader([]byte(*s)))
+		for _, err = d.Token(); err != io.EOF; {
+			_, err = d.Token()
+			if err == io.EOF {
+				err = nil
+				break
+			} else if err != nil {
+				return nil, err
+			}
+		}
 	}
 	return []byte(*s), err
 }