$(function() {

$("form#submit").submit(function() {

var id = $("#id").val(); 

var dataString = 'id='+ id;

$.ajax({

	type: "POST",

	url: "get_form.php",

	data: dataString,

	success: function() {

		$('#content').fadeOut('slow');

		$('#content').fadeIn('slow');

		$('#content').load("models.php");

	}

})

return false;

});

});

<form method="post" id="submit">

		<input type="hidden" id="id" value="1">

		<input type="submit" value="" class="submit">

	</form>