In order to prefill form fields, you need to create a customized URL for your web form. Normally, the link to your web form looks like this:
http://wix.123formbuilder.com/form-201140.html
where 201140 is your web form ID. To introduce preset field values, you need a different URL, of this type:
http://wix.123formbuilder.com/sf.php?s=123formbuilder-201140&control1111111=John&control2222222=Doe,
where sf.php?s=123formbuilder is the key part that remains unchanged for all customized URLs, 201140 is your web form ID and control1111111=John sets the preset value John for the form field with the ID 1111111.
Simply put, what you have to do is generate a URL that calls the ID of the form field for which you want to set a predefined value and assigns that value to it. You can prefill as many fields as you want within a form. URL parameter and value pairs are connected by ampersands (&). By pair of parameter and value, we understand control1111111=presetValue. In this structure, 1111111 is the form field ID.
You can find out what the IDs of your form fields are previewing your form link. After pressing the right mouse button, select Inspect Element and hover over your mouse cursor over your first field. The ID of the entire field will be listed after data-id.

Here is some useful information for using pre-filled form fields most efficiently. Note that we will use 1234567 as the form field ID. You will need to replace this example ID with the real IDs of your form fields.
- Preset values for the fields Text Box, Text Area, Number, Email, Website: You only need to include &control1234567=presetvalue in the webform URL. Replace presetvalue with the value of your choice and &control1234567 with your control (form field) ID.
- Preset values for the fields Name, Hour, Price: In this case, the form field is split into several subfields. For example, the field Name contains a First Name and a Last Name. These two have separate IDs: First Name – 1234567-1, Last Name – 1234567-2. Therefore, the right syntax will be &control1234567-1=John&control1234567-2=Doe. This goes for the Phone field, as well. If you’ve got more than two subfields, then go on using -3.
- Preset values for Phone: If you want to prefill the input of the Phone field, use this code: &control1234567=123-342-345. However, make sure you use the format you’ve selected for the field.
- Preset values for the Address field: An address field functions in the same way as the Name field, only that here you’ve got five subfields and, consequently, five IDs, form 1234567-1 to 1234567-5. In addition, there is the Country field, which is a dropdown list. To preset a value for the list of countries, you need the following code: &control1234567-6=CountryName.
- Preset values for Dropdown Lists and Radio Buttons: These fields allow for a single choice. This means that there is only one ID for the entire field. The syntax is &control1234567=ChoiceName, where ChoiceName is the choice that you want to preset.
- Preset values for Checkboxes: Since checkboxes allow for multiple choices, one single ID is not enough. Every option will have its own ID, in order to function like a separate subfield. To precheck an option, use this code: &control1234567-0=yes. As you can see, the first option is -0, next one -1, next one -2 and so on.
- Preset values for Likert Scales: Each Likert scales statement has an individual ID. To preset a value for a Likert statement, use the following code: &control1234567=Neutral, i.e. the value will be the name of the option that you want to have preset.
- To introduce white spaces in pre-filled form fields, use the code %20. For example, to obtain the preset value Fifth Avenue for a field, you will need the following code: &control1234567=Fifth%20Avenue.
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I have 123 form builder integrated with wix.com. I go this to work on my 123 form builder URL but not on my Wix Custom domain.
Here’s the form that works: https://wix.123formbuilder.com/sf.php?s=123formbuilder-4974676&control55879584-1=Henry
Here’s my custom domain (Doesn’t Work): https://www.beyondatrip.com/soflo-locals-docusign-verification/sf.php?s=beyondatrip.com-4974676&control55879584-1=Henry
What am I doing wrong?
In your cool shoes custom domain example, I noticed you just have the domain URL and /sf.php?s.
I have soflo-locals-docusign-verification than sf.php?s.
Does the page name have anything to do with it not working?
Appreciate the help.
Hi Henry!
The prefill can only be made on our own domain, since there we have control and store the data. On your own domain can not be made since it has no reference to our services/domain. The example you saw is made with a subdomain added to our forms. Here is our article explaining how the subdomain works on our side. The prefill will work if you use the direct link of your form.
So how would that work? Like this?
http://www.MYDOMAIN.com/sf.php?s=MYDOMAIN-123450&control1111111=John&control2222222=Doe,
Yes, after you have added your subdomain your custom URL will look like this: https://forms.yourdomain.com/sf.php?s=forms.yourdomain.com-formID&control111111=John&control2222=Doe
I made here an example with my subdomain (coolshoes.myfor.ms) : https://coolshoes.myfor.ms/sf.php?s=coolshoes.myfor.ms-4970320&control55733115=john&control55733116=Doe
How does this fit in when we are using white labeling?
Hello Casey! Even if you are using your own domain, the method of prefilling form fields will work, without any issues.
Good info. Lucky me I came across your blog by chance (stumbleupon).
I’ve saved it for later!
The Link to the blog entry is not working! Is there no FAQ on how to create the needed customized url?
Hi Michael. Thank you for bringing this to our attention. We have updated the article with all the necessary steps to create custom a URL.
If you need further assistance you can always contact our Customer Care team directly from your account or via live chat.
Thank you!
In the example URL: http://wix.123formbuilder.com/sf.php?s=123formbuilder-123450&control1111111=John&control2222222=Doe, where is the 201140 web form ID supposed to go?
Hello Michael! Your form ID will be inserted after s=123formbuilder-, more exactly instead of 123450.
Thanks