Signup forms can be used to collect many types of information. You might need a signup form for new members to sign up, contact you, or perhaps for them to order an item they wish to purchase from you. Once it has passed the checks, this information can then be processed in any way you require, sending an email to the user or yourself, or adding the data to a MySQL database. Another page is displayed confirming that the form has been successfully completed.
PHP can perform error checks on the information that a visitor enters into your form. This can be very useful, as users may make an obvious mistake, or simply forget to enter some important information. It also gives greater security for your website. Error checking can be as simple as checking that a field has not been left empty. Fields can also be checked to ensure that they are of the correct type - for example, names should only contain letters and phone numbers should only contain numbers and a few other characters. Email addresses and URLs can also be checked to ensure that they are in the correct format.
If an error is found, the original form is redisplayed, highlighting the area or areas where an error was found. This could be a short message or red lines around the relevant text box. All of the original data that was entered is redisplayed, making it simple for the user to correct their error and resubmit the form.
Once the signup process has been completed, an email can be sent to you containing all of the information, laid out exactly as you wish. This can be a plain text email or a HTML email. If you require, an email can also be sent to the person who completed the signup, confirming that they have completed the process and giving them a copy of all the information that they have given you.
If the form is for purchasing a product or service from you, the user can pay instantly using a payment gateway such as PayPal or NOCHEX.