on create job page, when typing in the job name text box, Jenkins call checkJobName api to check the item name, but this api always return an extra blank line in response body: "  <div/>"

It caused the UI disable the submit button and I could never create a job. Please see the screenshot attached.

An example of the checkJobName api call and response:
Request URL:
http://myjenkins.com/view/all/checkJobName?value=dfd
Response:

HTTP/1.1 200 OK Date: Thu, 22 Mar 2018 02:33:27 GMT Content-Type: text/html;charset=utf-8 Transfer-Encoding: chunked Connection: keep-alive Vary: Accept-Encoding X-Content-Type-Options: nosniff Server: Tengine/Aserver Strict-Transport-Security: max-age=0 Timing-Allow-Origin: * EagleEye-TraceId: 0a67792f15216860072187973e2e7b RequestUri: jenkins.qa.umeng.com/view/all/checkJobName RequestApp: jenkins.qa.umeng.com Content-Encoding: gzip

 
<div/>