jQuery iframe form submit

Is there any way to submit an iframed form from jQuery? What I have is the following:

$('button#bookingButton').click(function(){
    $('<iframe id="externalSite" class="externalSite" src="/form/page" />').dialog({
        title:'Form', 
        autoOpen: true, 
        width: 开发者_运维知识库800, 
        height: 600, 
        modal: false, 
        resizable: false,
        buttons:{
            'Close':function(){$(this).dialog("close");},
            'Add Booking':function(){$('form#bookingForm').submit();}
        }
    }).width(800 - 25);
});

This creates a jQuery ui dialog which has an iframe within it. This works fine and the regular submit button works fine however the jQuery button does not submit the form.

add this AFTER you insert the IFRAME into the DOM:

 $("#externalSite").contents().find('form').submit()