the first line defines the request typedocument (the selector)and protocol version following the request line is series of header lines containing various information about the clientsuch as passwordscookiescache preferencesand client software following the header linesa single blank line indicates the end of the header lines after the headerdata may appear in the event that the request is sending information from form or uploading file each of the lines in the header should be terminated by carriage return and newline ('\ \ ' the server sends response of the following formhttp/ ok content-typetext/html content-length bytes headerdata data the first line of the server response indicates the http protocol versiona success codeand return message following the response line is series of header fields that contain information about the type of the returned documentthe document sizeweb server softwarecookiesand so forth the header is terminated by single blank line followed by the raw data of the requested document the following request methods are the most commonmethod description get post head put get document post data to form return header information only upload data to the server the response codes detailed in table are most commonly returned by servers the symbolic constant column is the name of predefined variable in http client that holds the integer response code value and which can be used in code to improve readability table code response codes commonly returned by servers description symbolic constant success codes ( xx ok created accepted no content ok created accepted no_content redirection ( xx multiple choices moved permanently moved temporarily not modified multiple_choices moved_permanently moved_temporarily not_modified lib fl ff