A custom validation rule that is checked asynchronously. Use async rules for server-side validation.
Validation rules are checked in the following order: All the synchronous rules are checked in the same order as in the validationRules array. Then, all the async rules are checked simultaneously.
A validation rule that demands that a validated editor has a value that is equal to a specified expression.
To specify the expression that the validated field must match, set the rule's comparisonTarget configuration option. Assign a function to this option. The validated value will be compared to the function's return value. The comparison will be performed by using the operator that is set for the comparisonType option.
A validation rule that demands the target value be within the specified value range (including the range's end points).
Use this rule type to ensure the target editor value is specified. The rule will be broken in the following cases.
- If the validated value is null, false, or undefined.
- If the specified value has a type that is not expected for the target field (e.g., a string for the DateBox widget).
A validation rule that demands the target value length be within the specified value range (including the range's end points).