Set content of iframe

I managed to do it with

var html_string= "content";
document.getElementById('output_iframe1').src = "data:text/html;charset=utf-8," + escape(html_string);

Use the "contents" function:

$('#some-id').contents().find('html').html("some-html")

Relevant fiddle: http://jsfiddle.net/fDFca/