The base "layout.html" view is expected to handle DIVs of class "error".
The default layout uses j Query effects to make errors appear and slide down with a red background. or can be a function that takes the form and returns nothing.
All these forms are self-aware and, if the input does not pass validation, they can modify themselves and add error messages.
The forms can be queried for the validated variables and for error messages that have been generated by validation.
Arbitrary HTML code can be inserted into or extracted from the form using helpers. Since web2py processed the form in the action, it is better to define the form in the action itself. A form is not accepted if it has errors or when it has not been submitted (for example, the first time it is shown).
along with its provided value is displayed at the bottom. Here is how this page looks the first time it is displayed: Here is how it looks upon invalid submission: Here is how it looks upon a valid submission: A shortcut for is a query and uses the same DAL syntax that you use for database queries.
Here is an example: When filling a form to edit a record there is a small probability that another user may concurrently be editing the same record.
So when we save the record we want to check for possible conflicts.This can be done: works only with a SQLFORM and not with a FORM.The difference is that this query not sent to the database but it is converted to Java Script and sent to the browser where it is executed when the user edits the form.When the above form object is serialized by The role of these hidden fields and their usage in custom forms and pages with multiple forms is discussed in more detail later in the chapter.If the form above is submitted with an empty "name" field, the form does not pass validation.When the form is serialized again it appears as: method, upon submission, determines that the form is submitted, checks whether the field "name" is empty and whether it is required, and eventually inserts the error message from the validator into the form.