Validating inputs in
If you haven't already, make sure that you've included the j Query library on your page: Since the name field is required, we simply need to check whether a value for the input exists.If it exists, we'll apply the valid class and remove any invalid class.
However, to see whether a credit card has sufficient funds requires communicating with the credit card company and that can only be done using a server side programming language.When the submit button is pushed, j Query will check whether all fields are valid.If any fields are not valid, the form will not be submitted and the user will be informed with error messages for the fields that are causing problems.The only difference is that now we want to check whether the email address looks like an email address.We know that email addresses should include an @ symbol and end with a feasible domain name. Regular expressions are a programming language for parsing text.If you are using a My SQL database, this is called My SQL Injection.
To avoid this problem, you must validate form submissions using your server.
In client side validation the data is validated in the browser using Java Script before submitting the data to the server.
For example, suppose your user submits the form without entering a mandatory field.
Similarly, form data is typically saved in a database on the server.
Because your database contains sensitive information, hackers may attempt to use your form to submit malicious commands to your backend database.
However, if Java Script is turned on, our validation will solve any problems before the browser sees them.