validate Empty ( ) The function below checks if a required field has been left empty.If the required field is blank, we return the error string to the main function.We want to allow only letters, numbers and underscopes.
Also, the @ must not be the first character of the email address, and the last dot must at least be one character after the @ sign.
At first we check if the user entered anything at all in the email field.
We will check the password strength using a few regular expressions with j Query.
Figure 1: Displays the Password text field Calculating the Password Strength: We need to think of some rules for the password, so that we can evaluate the password strength based on those rules.
Any interactive web site has form input - a place where the users input different kind of information.