How to set up error checks
Add markers like ###error_[fieldname]### to your template and set up validation in TypoScript:
plugin.Tx_Formhandler.settings.validators.1 {
  class = Validator\DefaultValidator
  config {
    fieldConf {
      field1 {
        errorCheck.1 = required
        errorCheck.2 = maxLength
        errorCheck.2.value = 50
      }
      field2 {
        errorCheck.1 = required
        errorCheck.2 = email
      }
    }
  }
}
		
			
		
	Add entries for error messages to your translation file
<label index="error_field1_required">Field1 is required!</label> <label index="error_field1_maxLength">Field1 has to be shorter than ###value### characters!</label> <label index="error_field2_required">Field2 is required!</label> <label index="error_field2_email">Field2 is no valid e-mail!</label>
NOTE: The marker ###value### in the error message is filled with the value of the parameter “value” for error check “maxLength”. If an error check requires parameters, you can use markers like ###[parametername]### in the translatable message.
When you have to validate values in nested arrays you can nest the validators as well. Given the following fields:
<input type="text" name="birthdate[day]"/> <input type="text" name="birthdate[month]"/> <input type="text" name="birthdate[year]"/> <input type="text" name="name"/>
You can setup your validators like that:
validators.1.config.fieldConf {
  birthdate {
    day.errorCheck {
      1 = betweenValue
      1.minValue = 1
      1.maxValue = 31
    }
    month.errorCheck {
      1 = betweenValue
      1.minValue = 1
      1.maxValue = 12
    }
    year.errorCheck {
      1 = minValue
      1.minValue = 45
    }
  }
  birthdate.errorCheck.1 = maxItems
  birthdate.errorCheck.1.value = 3
  name.errorCheck.1 = required
}
		
			
		
	The errors for the birthdate array will then be merged into the marker ###error_birthdate###.
