Hotmail and Outlook issues with radio buttons

Question

Recently I implemented a system where customers could give feedback about customer service in an email. The email sent to them included two radio buttons, a comment text entry box, and a submit button. The solution was tested in Gmail and worked perfectly, however we have been getting reports that there are issues with Hotmail, Outlook, and for all we know others too.

After testing in Hotmail we found the radio buttons could not be selected, and the submit button did not do anything, whereas in Outlook the entire thing displayed as text.

The email is sent from the Salesforce platform and the HTML is as follows:

<p>Hi {!recipient.name},</p>

<p>An issue you raised with us has been marked for closure. We would
appreciate if you could take a few seconds to just let us know whether 
you were satisfied with the resolution.</p>

<p>Your case is number: {!relatedTo.CaseNumber}. The subject for your case is: {!relatedTo.Subject}.</p>

<form method="post" action="www.oursite.com/feedback.php" onsubmit="Disable()">
<input type="radio" name="yesno" value="This issue was resolved." checked="true">This issue was resolved.</input><br></br>
<input type="radio" name="yesno" value="This issue was not resolved">This issue was not resolved.</input>
<p>Anything else we should know? <input type="text" name="comments"></input></p>
<input type="hidden" name="cust" value="{!recipient.name}"></input>
<input type="hidden" name="caseendid" value="{!relatedTo.CaseNumber}"></input>
<input type="hidden" name="caselink" value="https://eu1.salesforce.com/{!relatedTo.Id}"></input>
<input type="submit" name="submit" value="Submit"></input>
</form>

<script>
function Disable()
{
var button;
button = document.getElementByName('submit');
button.enabled = false;
}
</script>

Anything enclosed in {!some.value} is replaced by text by salesforce before being sent. Can anyone shed any light on why we're having issues in Hotmail or Outlook as there doesn't really seem to be much on MSDN or here already regarding this?

Answer 1

<form>s and HTML formatted email mix very, very poorly.

Send people a feedback link instead and use an identifying token in it to pre-populate (with any identifying data you like) a form in a regular web page hosted on a regular http(s) website.

(You can give them a plain form and a link without an identifying token if you don't have any data you want to pre-populate it with).