HTML and CSS Reference
If false is returned, the form is stopped, and will not be submitted.
The HTML form, called mailchk , starts here. The onSubmit event will be triggered
when the user clicks the submit button on line 7.
The form's input type is a textbox named address that will hold up to 60 characters.
When the user clicks the submit button, the onSubmit handler on line 5 is trig-
gered. It invokes the handler function, called email , and passes a reference to the
form as an argument. See Figures 11.48 and 11.49.
Figure 11.48 The user enters a valid e-mail address.
Figure 11.49 The user enters an invalid e-mail address. A dot is missing in the address.
Checking Password Fields. There are a number of checks made on password
entries. Does it have the right number of characters? Does it contain one numeric char-
acter? Can it contain upper and lowercase characters? The following example is a simple
validation routine to check for alphanumeric characters and that the number of charac-
ters in the password field is not less than six.