Validating text files
You cannot rely on Java Script to avoid this security problem. You can also download this demo and check out the source as we go through this tutorial.
Because your database contains sensitive information, hackers may attempt to use your form to submit malicious commands to your backend database.
For example, suppose you wanted to validate a credit card.
All credit cards are 16 digits and the 16th digit can be calculated based on the first 15 numbers.
The following attributes are used to describe basic constraints: Constraint validation is done through the Constraint Validation API either on a single form element or at the form level, on the This displays the following form: The Java Script reads the file selected, uses the You can see a live example of the File size constraint validation.
Apart from setting constraints, web developers want to control what messages are displayed to the users and how they are styled.