The server side form validations help keeping the form submission data consistent.
When you have fields like name or email as mandatory in the form, it should be checked in the server side script as well. Here is the sample output from that script: Note that the “Filling” checkbox group in the HTML form results in an array in the PHP script The rest of the fields appear as simple name-value pairs To validate mandatory fields, we just have to check the presence of the value in the $_POST array.
(note that the form method is post in the HTML form).
Client-side form validations help in giving immediate feedback to the user.
As a example you may need to select preferred subjects of a student(Maths, Science, English etc.).The validations also help in lesser server side errors.For example, if you have set length limit in the database for a text input, it is better to do the validation before it actually gets cut off by the database system or even getting an error thrown.Then you can just check for ’emptiness’ : For dropdown lists, we are to set the ‘selected’ attribute for previously selected item.Check box groups are great when you want to allow multiple options for a field. We need to validate that at least two options are selected.Very first we have to create a form in html setting action “#” and method “POST” with some fields, when a user clicks on submit button all the data starts travel in URL but it will be hidden, as we set method = “POST”.how can I stop the request process after the checkbox validatation?I want to stop the request if the checkboxes has never selected.The below script will not stop the process even it success validate no checkbox is select.Form validation is focussed towards the user input where as the security validations should be focused on how you use the data.When you use the form data in an SQL query, it should be validated against SQL Injection.