Contact form for HTML

[Crystal]

Hey guys,
I have recently designed a website for someone but the issue is the contact form.. I have used the following code for the contact..

Code:

<form action="mailto:email@yahoo.com" method="post" id="sendemail">
          <ol><li>
            <label for="name">Name (required)</label>
            <input id="name" name="name" class="text" />
          </li><li>
            <label for="email">Email Address (required)</label>
            <input id="email" name="email" class="text" />
          </li><li>
            <label for="website">Website</label>
            <input id="website" name="website" class="text" />
          </li><li>
            <label for="message">Your Message</label>
            <textarea id="message" name="message" rows="8" cols="50"></textarea>
          </li><li>
            <input type="image" name="imageField" id="imageField" src="images/submit.gif" class="send" />
            <div class="clr"></div>
          </li></ol>
          </form>

When a client click on the submit button it opens the users email client like outlook express/thunderbird... Instead I want when the submit button is clicked it should send the email to the desired email address directly instead of through the email client..

I would appreciate if some one could help me through this!
Thanks in advance.