Open Outlook and preset email, subject and body using HTML/Javascript

I am new in Javascript and I would like to make a small offline tool that opens up Outlook, and presets the email in the "To" section, presets the default Subject, and presets the body of the email with text from a textarea.

I would need the text area so that I can modify the email content whenever I want.

For now, I have the following code:

<form method="post" action="mailto:yourname@yoursite.com" enctype="text/plain">
   <input type=text name=your_content>
   <input type=submit value="Submit Your Content">
</form>

However, when I submit, Outlook opens, and the name attributes' values appear before my text.

Is there a way to avoid adding the name's value in my email, replace input with textarea and add the above mentioned things?

Thanks!