Phpheader () function details and instance _ PHP Tutorial

Phpheader () function details and examples. Php Tutorial header () function detailed introduction and instance syntax header (string, replace, http_response_code) parameter description string required. Specifies the header string to be sent. Replace is optional. Instructions php Tutorial header () function details and examples
Syntax
Header (string, replace, http_response_code) parameter description
String is required. Specifies the header string to be sent.
Replace is optional. Indicates whether the header replaces the previous header or adds the second header.

The default value is true (replace ). False (multiple headers of the same type are allowed ).

Http_response_code is optional. Forces the http response code to the specified value. (Php 4 and later versions are available)

The header () function sends the original http header to the client.

It is important to realize that the header () function must be called before any actual output is sent (in php 4 and later versions, you can use the output cache to solve this problem):

*/
Header ("x-sample-test: foo"); // send the http header
Header ('content-type: text/plain '); // send the http header
Var_dump (headers_list (); // returns the list of sent headers.

If (! Headers_sent () // if the header is not sent
{
Header ('Location: http://www.example.com/'); // send the header
Exit; // end the php code
}
If (! Headers_sent ($ filename, $ linenum) // if no specified file is output
{
Header ('Location: http://www.example.com/'); // send the header
Exit; // end the php code
}
Else // if it has been output to the specified file
{
Echo "headers already sent in $ filename on line $ linenumn ".
"Cannot redirect, for now please click this" href = "http://www.example.com"> linkinsteadn "; // output prompt information
Exit; // end the php code
}
/*
Note: After php 4.4, this function prevents multiple headers from being sent at a time. This is a protection against header injection attacks.

*/

The response header () function is required to describe string with the instance syntax header (string, replace, http_response_code. Specifies the header string to be sent. Replace is optional. Instructions...