function input Alphabet(inputtext, alert Msg) // Function that checks whether input text includes alphabetic and numeric characters.

Form validation helps us achieve these goals — this article tells you what you need to know.

This is called form validation — when you enter data, the web application checks it to see if it is correct.

attribute to turn off the browser's automatic validation; this lets our script take control over validation.

However, this doesn't disable support for the constraint validation API nor the application of the CSS pseudo-class or other As you can see, the HTML is almost the same; we just removed the HTML validation features.

] @[a-z A-Z0-9.] .[a-z A-Z0-9]$/ The expression checks the letters, numbers, and other symbol at a proper sequence.

The sequence is defined as: [alphabets/numbers/underscore/plus [email protected]/numbers/periods.domain name] If the entered email address is not in a proper sequence, then the message will popup which says “Wrong Email Address”.

Regular expression helps you in pattern matching in string. : Matches any single charcter except a new line : Matches the preceding character or repeated character. The basic expression for matching entered value as number in the field is: /^[0-9] $/.

[A-Z] : It matches characters from uppercase ‘A’ to lowercase ‘Z’. The codes for checking form empty fields are given below: There is an expression that checks whether the string contains only alphabets or not.

Checking for form completion: The first step of form validation is to check, whether the user have entered information in all the fields or not.

If the string value is numeric, it will return true, otherwise it will return false.

It happens sometimes, when user forgets to choose option from the select feild.