You can use the ajaxForm/ajaxSubmit functions from Ajax Form PluginAjax Form Plugin or the jQuery serialize function.
AjaxForm:
$("#theForm").ajaxForm({url: 'server.php', type: 'post'})
or
$("#theForm").ajaxSubmit({url: 'server.php', type: 'post'})
ajaxForm will send when the submit button is pressed. ajaxSubmit sends immediately.
Serialize:
$.get('server.php?' + $('#theForm').serialize())
$.post('server.php', $('#theForm').serialize())