{"json_modified": "2016-07-19T05:23:12.236323", "uuid": "02166452-ccf2-4c8a-84f7-fcc75cc1728a", "title": "Request header", "url": "/en-US/docs/Glossary/Request_header", "tags": ["glossary", "WebMechanics", "Glossary"], "translations": [], "modified": "2016-07-19T05:23:12", "label": "Request header", "localization_tags": [], "locale": "en-US", "id": 188829, "last_edit": "2016-07-19T05:23:07", "summary": "A <strong>request header</strong> is an <a class=\"glossaryLink\" href=\"/en-US/docs/Glossary/header\" title=\"HTTP header: An HTTP header is a field of an HTTP request or response that passes additional information, altering or precising the semantics of the message or of the body. Headers are case-insentive, begins at the start of a line and are immediately followed by a ':' and a value depending of the header itself. The value finish at the next CR or at the end of the message.\">HTTP header</a> that can be used in an HTTP request, and that doesn't relate to the content of the message. Request headers, like <a href=\"/en-US/docs/Web/HTTP/Headers/Accept\" title=\"The documentation about this has not yet been written; please consider contributing!\"><code>Accept</code></a>, <a href=\"/en-US/docs/Web/HTTP/Headers/Accept-Language\" title=\"The documentation about this has not yet been written; please consider contributing!\"><code>Accept-*</code></a>, or <a href=\"/en-US/docs/Web/HTTP/Headers/If-Modified-Since\" title=\"The documentation about this has not yet been written; please consider contributing!\"><code>If-*</code></a> allow to perform conditional requests; others like <a href=\"/en-US/docs/Web/HTTP/Headers/Cookie\" title=\"The documentation about this has not yet been written; please consider contributing!\"><code>Cookie</code></a>, <a href=\"/en-US/docs/Web/HTTP/Headers/User-Agent\" title=\"The documentation about this has not yet been written; please consider contributing!\"><code>User-Agent</code></a> or <a href=\"/en-US/docs/Web/HTTP/Headers/Referer\" title=\"The documentation about this has not yet been written; please consider contributing!\"><code>Referer</code></a> precise the context so that the server can tailor the answer.", "sections": [{"id": "Learn_more", "title": "Learn more"}, {"id": "Technical_knowledge", "title": "Technical knowledge"}], "slug": "Glossary/Request_header", "review_tags": []}