renderform ignore struct field if form tag value is '-'

@@ -282,20 +282,24 @@ func RenderForm(obj interface{}) template.HTML {
 		fieldT := objT.Field(i)
 		tags := strings.Split(fieldT.Tag.Get("form"), ",")
 		name := fieldT.Name
-		if len(tags) < 2 {
+		fType := "text"
+		if len(tags) > 0 && tags[0] == "-" {
+			continue
+		}
+
 		if len(tags) == 1 && len(tags[0]) > 0 {
 			name = tags[0]
-			}
-			raw = append(raw, fmt.Sprintf(`%v: <input name="%v" type="text" value="%v">`,
-				fieldT.Name, name, fieldV.Interface()))
-		} else {
+		} else if len(tags) >= 2 {
 			if len(tags[0]) > 0 {
 				name = tags[0]
 			}
-			raw = append(raw, fmt.Sprintf(`%v: <input name="%v" type="%v" value="%v">`,
-				fieldT.Name, name, tags[1], fieldV.Interface()))
+			if len(tags[1]) > 0 {
+				fType = tags[1]
 			}
 		}
+		raw = append(raw, fmt.Sprintf(`%v: <input name="%v" type="%v" value="%v">`,
+			fieldT.Name, name, fType, fieldV.Interface()))
+	}
 	return template.HTML(strings.Join(raw, "</br>"))
 }
 

@@ -150,10 +150,11 @@ func TestParseForm(t *testing.T) {
 
 func TestRenderForm(t *testing.T) {
 	type user struct {
-		Id    int
-		tag   string      `form:tag`
+		Id    int         `form:"-"`
+		tag   string      `form:"tag"`
 		Name  interface{} `form:"username"`
 		Age   int         `form:"age,text"`
+		Sex   string
 		Email []string
 		Intro string `form:",textarea"`
 	}
@@ -165,9 +166,9 @@ func TestRenderForm(t *testing.T) {
 	}
 	output = RenderForm(&u)
 	result := template.HTML(
-		`Id: <input name="Id" type="text" value="0"></br>` +
 		`Name: <input name="username" type="text" value="test"></br>` +
 			`Age: <input name="age" type="text" value="0"></br>` +
+			`Sex: <input name="Sex" type="text" value=""></br>` +
 			`Intro: <input name="Intro" type="textarea" value="">`)
 	if output != result {
 		t.Errorf("output should equal `%v` but got `%v`", result, output)