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Forms Copied And Pasted To Unauthorized Web Sites

By Will Bontrager

There is no way I'm aware of to prevent people from copying your web page form (or any other web page, for that matter) and publishing it on their own web site. However, JavaScript can be used to make some features on the web page operable only when the page is on an authorized domain. On unauthorized domains, the features don't work.

This post is specifically oriented for those who are having problems with others copying their forms and pasting them on unauthorized web sites. The concept, however, can be applied to other web page features — search boxes or cookies, as examples.

For the form, two things are done:

1. The submit button is disabled. This is hard-coded right into submit button form field. The attribute is: disabled="disabled"

2. JavaScript is put below the form to enable the submit button if, and only if, the form is on the authorized domain.

The form must have a name and the submit button must have a name. And the JavaScript needs to be customized to specify the authorized domain.

Here is the code, with an example form and the JavaScript to enable the submit button.

<form name="myForm" method="POST" action="/cgi-bin/script.cgi"> <input name="mySubmit" disabled="disabled" type="submit" value="Click Me"> </form> <script type="text/javascript" language="Javascript"> // In the value below, specify only the domain name, not the // http:// part nor the rest of the URL. If the domain name // begins with www. then omit that part, also. The script // will check if the web page is on the domain you specify // and it will also automatically check with a leading www. var DomainName = "example.com"; var FormName = "myForm"; var SubmitName = "mySubmit"; // Modify the above values as appropriate. if( (location.hostname.indexOf(DomainName)==0) || (location.hostname.indexOf(DomainName)==0) ) { eval('document.'+FormName+'.'+SubmitName+'.disabled=""'); } </script>

As an aside, if you are having problems with others hotlinking to image and other file on your server without authorization, or wish to know if it has been going on without your knowledge, here are two articles you will find of interest:

• Almost 2000 Hotlinks Reported
• Hotlink Alarm Detects 284 Hotlinks Shortly After Installation

June 21, 2008

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