phpheaderoutput

2015年10月17日—Youhavetosettheheadersbeforeanyoutput,whichincludesthe.·Don'tsettheheaderbeforeanyechoandprintstatement.– ...,2017年9月17日—header()mustbecalledbeforeanyactualoutputissent,eitherbynormalHTMLtags,blanklinesinafile,orfromPHP.Itisaverycommon ...,2023年3月31日—PHPheaderisaninbuiltfunctionthatisusedtosendarawHTTPheadertotheclientanditismandatorythattheyactuallyman...

參考資訊如下
How to set Headers correctly in PHP

2015年10月17日 — You have to set the headers before any output, which includes the <!doctype html> . · Don't set the header before any echo and print statement. – ...

Call header() after output is sent [duplicate]

2017年9月17日 — header() must be called before any actual output is sent, either by normal HTML tags, blank lines in a file, or from PHP. It is a very common ...

Complete Guide to PHP header() with Examples

2023年3月31日 — PHP header is an inbuilt function that is used to send a raw HTTP header to the client and it is mandatory that they actually manipulate the ...

getallheaders

An associative array of all the HTTP headers in the current request, or false on failure. Changelog ¶. Version, Description. 7.3.0, This function became ...

header

Remember that header() must be called before any actual output is sent, either by normal HTML tags, blank lines in a file, or from PHP. It is a very common ...

headers_list

Headers will only be accessible and output when a SAPI that supports them is in use. See Also ¶. headers_sent() - Checks if or where headers have been sent ...

headers_sent

Output buffering allows you to send header lines (including cookies) even after you send body content, in the price of slowing PHP's output layer a bit.

header_register_callback

Registers a function that will be called when PHP starts sending output. The callback is executed just after PHP prepares all headers to be sent, and before ...

Header in PHP

2021年6月17日 — The header() function in PHP sends a raw HTTP header to a client or browser. Before HTML, XML, JSON, or other output is given to a browser or ...

PHP header() Function

The header() function sends a raw HTTP header to a client. It is important to notice that the header() function must be called before any actual output is sent!