Validating user input
If you are sending sensitive data such as passwords, emails with HTTP request you must use POST. But, if the email is compulsory, we have to throw an error if it's empty.
If you are retrieving data from the server, you can use GET method. Here I have chosen POST method and the action script, is requested with any other method, it will show an error. Next, we have to check the user inputs to avoid processing errors. Assume that you have php code to assign POST variable to a local variable as following. The last subtopic of this tutorial will explain you to do that in an object oriented way. We save his username in the database without any validation.
Here is how it appears in Safari (with our CSS formatting to show the (in)valid state): In a similar fashion to the Again, the input box appears as normal: This time the minimum requirement for most browsers is one or more letters followed by a colon. :[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f] | \[\x01-\x09\x0b\x0c\x0e-\x7f]) ) \])\z Or you can look here for more solutions.
Again, not very helpful, but it will stop people trying to input their email address or other such nonsense. Careful examination of the RFCs associated with email addresses has been conducted repeatedly and has been proven to require the use of recursion in order properly determine the validity of an email address using the full set of RFC specifications.
This function returns false on failure or invalid input.1.
We can set it's second parameter to different values and use it to validate emails, URLs, integers, booleans, etc.
This method can be used to validate any integer value such as a primary integer key (user Id, group Id, etc.) in database, timestamp, etc.
The advantage of using this function is, it converts string numbers ( function.
For a more detailed introduction to HTML5 form validation you can find some great articles linked under References below.
In this article we intend to present only a number of simple examples to get you started, covering the basic form elements.