AJAX 异步传输数据的问题

var postData = "input="+ escape(inputJSON) +"script="+escape(xml)+
"feedGeneral=" + escape(feedGeneral);
XmlHttpRequest.open("POST",url,true);
XmlHttpRequest.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
XmlHttpRequest.send(postData);

Control names and values are escaped. Space characters are replaced by `+', and then reserved characters are escaped as
described in [RFC1738], section 2.2: Non-alphanumeric characters are replaced by `%HH', a percent sign and two hexadecimal
digits representing the ASCII code of the character. Line breaks are represented as "CR LF" pairs (i.e., `%0D%0A').

$('test').innerHTML = "form target='_blank' id='test_form' action='./gen_feed' method='post'>"
+ "input type='text' name='input' />input type='text' name='script' />"
+ "input type='text' name='feedGeneral' />input type='hidden' name='format' value='" + this.feed_type + "'
/>"
+ "input type='submit' value='gen' />/form>";
var test_form = $('test_form');
test_form.elements[0].value = inputJSON;
test_form.elements[1].value = script;
test_form.elements[2].value = feedGeneral;
test_form.submit();