How to pre fill a textbox based on ID and submit in email

Hi, i am attempting to pre-fill a textbox using the ID elements of my favourite button and then submitting the text box with mailto as a button etc. I am having difficulties going about using ID’s

      <fieldset data-role="controlgroup" data-type="horizontal">
          <input type="checkbox" name="favourite1" id="favourite1" class="custom">
          <label for="favourite1"><span class="ui-icon-star ui-btn-icon-left">Add to favourites</span></label>
<div data-role="page" id="favourites">
 
  <div data-role="header" data-position="fixed"> <!-- header-->
    <h1>Favourites</h1>
  </div>
  
  <div role="main" class="ui-content"> <!-- main contain-->
  
   <h1>Favourites</h1>

      <div id="favourite-content"><p>My favourites: </p></div>
	  
	<form action="mailto:moksuhd.khan@gmail.com Feedback" method="post" enctype="text/plain">
		Email Adress:<br />
	<input type="text" name="email_address" value="" maxlength="100" /><br />

	<input type="submit" value="Submit" />

	</form>
	  
  </div> <!-- end main contain-->

script (document).on( 'pagecontainerbeforehide', 'body', function( event, ui){ //do something if ( ui.nextPage.attr('id')== "favourites") { ("#favourite-content").html ("");
if (( "#favourite1" ).is( ":checked" )) { ("#favourite-content").prepend(’’);
}
if (( "#favourite2" ).is( ":checked" )) { ("#favourite-content").append(“

item2 details

”);
}

	  }
   
   });

Here is my site Read-Only: LINK
(how to share your site Read-Only link)