function length Define(inputtext, min, max) // Function that checks whether a option is selected from the selector and if it's not it displays an alert message.function true Selection(inputtext, alert Msg) // Function that checks whether an user entered valid email address or not and displays alert message on wrong email address format.It happens sometimes, when user forgets to choose option from the select feild.In that case, the form should convey about issue so that user can take the action.So, just to make sure that user entered the email address in the correct format, it’s necessary to include email validation code inside the validation codes.A general expression to check valid email address is: /^[w-.By combining the expression for numbers and alphabetic characters, there is an expression that checks, whether the entered things includes numbers and alphabetic character or not.The expression for matching numbers and characters in the field is: /^[0-9a-z A-Z] $/ It’s must to provide validation in the select field.
So the user can input more than number of allowed characters as long as they enter a new line.
Sometimes situations arise ( suppose a user id, password or a code) when the user should fill a single or more than one field with alphabet characters (A-Z or a-z) and numbers (0-9) in an HTML form.
You can write a Java Script form validation script to check whether the required field(s) in the HTML form contains only letters and numbers.
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.