Chrome Version       : 51.0.2704.84
URLs (if applicable) :
Other browsers tested: OK
  Add OK or FAIL, along with the version, after other browsers where you
have tested this issue:
     Safari:
    Firefox: 38.8.0
         IE: 11.0.9600.18230

What steps will reproduce the problem?
(1) jQuery synchronous ajax  on success update the select control (select.empty().html(response);)
(2) Another jQuery ajax parallel call on success update the same select control 
(3) Browser not responding it crashes.

What is the expected result?

Before updated the latest version of browser. Quite good. Should not crash.

What happens instead?
Browser not responding and force to kill the browser.

Please provide any additional information below. Attach a screenshot if
possible.