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JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.

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    How can I inject a value into a hidden form field?

    Asked by jrwcreativegroup on January 17, 2014 at 03:38 AM

    I am using asp.net and i want to inject a userid into a form field.  The user id will come from a cookie.

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    JotForm Support

    Answered by ashwin_d on January 17, 2014 at 07:03 AM

    Hello jrwcreativegroup,

    You can add a "Hidden Box" in your form which can be found under "Widgets" tab:

    Once you have hidden box in your form, you can use URL parameter feature to populate the hidden  box with a value. This guide should help you understand url parameters:  https://www.jotform.com/help/71-Prepopulating-fields-to-your-JotForm-via-URL-parameters

    You can also add the value through your codebehind or through javascript if you are using your form's source code to embed your form.

    I have created a demo form for you. Take a look :  http://form.jotformpro.com/form/40162880274958?userId=12345

    This form has a hidden field named userId which I am populating through url parameters. You need to refer the guide to understand the naming of the form fields to use in url parameter. URL parameter is something very similar which you use in ASP.NET and call it query string.

    Feel free to clone this form to take a closer look. This guide should help you in form cloning: https://www.jotform.com/help/42-How-to-Clone-an-Existing-Form-from-a-URL

    Hope this helps.

    Do get back to us if you have any questions.

    Thank you!