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jQuery and AJAX response header
If the server is returned data in response header how I can read it. I am sending an AJAX request to a server. It does not return anything but the Location in response header. I want to read that location using JavaScript or jQuery....
Both XMLHttpRequest and jqXHR (which is the object jQuery wraps around AJAX requests) have a getResponseHeader() method, so in the always() handler (jQuery) or readyState handler (XMLHttpRequest), do this.getResponseHeader('Location').
Bear in mind that if your server also sends a redirect status code (301/ 302) that redirect will be automatically followed, and there's no way to access the intermediate-headers returned.
In JavaScript, using XMLHttpRequest you can do that using getAllResponseHeaders() method.
jQuery also allowing to call that method. See more.
来源：https://stackoverflow.com/questions/10548990/how-to-get-read-data-from-response-header-in-jquery-javascript