Passing data in a hyperlink (HTTP GET)
Data can be passed by appending Certain name-value pairs in the hyperlink that contains the URL of the form.
Example: To pass the username jfkennedy@whitehouse.gov and password “jackie” to the form, use the following hyperlink:
https://www.certain.com/system/profile/form/index.cfm?PKformID=0x1219985d6&username=jkennedy@whitehouse.gov&password=jackie
Note that the Password field must be set to "Hide Text? = No" in order to pre-populate that form field.
You can change this setting on the Form's > Entry page in your event.
The URL for your online registration form is found on the Form's > Setup page.
Passing data in a form submission (HTTP POST)
You can also pass data to the first page of the Certain online registration form by posting a form submission to the URL of the registration form and passing the Certain variables as hidden fields.
<form action="https://www.certain.com/event/profile/form/index.cfm?PKformID=0x21239a912" method="POST">
<input type="hidden" name="username" value="jkennedy@whitehouse.gov">
<input type="hidden" name="password" value="jackie">
<input type="submit" name="go" value=" Online Now">
</form>
Advanced developers can achieve the same result using JavaScript or server-side commands.
The POST method of data transfer has several advantages over GET:
- The amount of data that you transfer in a GET statement is limited by the browser that the attendee is using, and, in general, it should be less than 1024 characters total.
- There is no limit to the amount of data that you can transfer via the POST method.
- The POST method is transparent to the attendee, while the GET method shows the data being transferred in the URL.
- Either method allows secure transmission of data, by using the "https" protocol instead of "http".
- Whether encrypted or not, the data is exposed on the Internet with either method, however, the POST method is more "psychologically secure" because end users cannot see their data in the browser's address window.
Important items to consider
- Passing personal data and passwords in a URL presents a privacy and security risk, therefore, we recommend using SSL transmission (a secure method using the https:// protocol) when using the methods described above.
- Data passed via a hyperlink or form submission will appear in the form fields to the registrant, but it will not be saved until the registrant submits that page of the online registration form.
- The data of any fields passed to Certain will override data that may have been contained in the database, e.g., for an attendee who has already registered and is returning to modify their record.
- Variables passed via form submission reside only on the first page of the online registration form. This means that if you pass the pro_lname field in the HTTP POST, but the “Last Name” field is not collected on the first page of the registration form, then this field will not be pre-populated on later pages. This is not the case with the hyperlink method, where passed variables are forwarded automatically to all subsequent pages of the registration form.
- When passing values in a URL using a custom registration question, the "®" will change to the registered trademark symbol and you will get an error (® is URL encoding for the registered trademark character).
- (Incorrect)
http://www.certain.com/event/profile/form/index.cfm?PKformID=0x33042a978®_ans_field04=Testing123
- (Correct)
http://www.certain.com/event/profile/form/index.cfm?reg_ans_field04=Testing123&PKformID=0x33042a978
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