PHP implementation of HTML source code in the carriage return line output

In the source code to enter a newline but do not display such as BR characters we need to escape the characters in PHP to achieve, the following is a look at it.

   

Knowledge expansion

[/td> >

transition sequence	description
n	line wrap
r	return
horizontal tab
backslash
$	$ sign
"	double quotes
[0-7]{1,3}
x[0-9a-fa-f]{1,2}	This regular expression sequence matches a character represented in hexadecimal notation

Using double quotes (") to define a string, PHP knows more about the escape sequence for special characters:

PHP default page encoding is HTML, for the output of the content to wrap, you must use the HTML Line wrap label "<br>" or "<br/>"
, when using PHP to do the HTTP API, processing the BR tag is a bit cumbersome, you can specify the PHP page encoding, so that "\ n" successfully resolved to wrap.

The code is as follows	Copy Code
<?php Header ("Content-type:text/txt; charset=gb2312 "); for ($i =0; $i < $i + +) { echo "string"; echo "\ n"; ?>

With a browser, 100 line "string" is displayed directly.
You can also declare the page encoding as

The code is as follows	Copy Code
Header ("Content-type:plain/text; charset=gb2312 ");

In this case, access to the browser, will automatically download as a document, with code to download no difference.

TXT file line breaks do not work when using fwrite newline write

We all know the line break in PHP: \ n, carriage return: \ r, when you need to change lines, it's usually a combination of "\ r \ n". But why does the newline character not work when we write a file using fwrite? Let's look at the following example:

The code is as follows
<?php $filename = ' file.txt '; $word = ' Hello! \ r \ n Welcome to Www.111cn.net '; $fh = fopen ($filename, "a"); W writes a append write from the beginning Echo fwrite ($fh, $word); Fclose ($FH); ?>

A carriage return line character "\ r \ n" is added to the $word string, but the output is not expected, and the carriage return line character "\ r \ n" is not resolved to be a newline character, but is directly treated as a char output.

Why is there such a situation? After study, the original is a single double quotation mark to cause trouble! We put the single quotation mark "'" of the $word definition string into double quotation marks "". The correct wording is as follows:

The code is as follows
<?php $filename = ' file.txt '; $word = "Hello!" \ r \ n Welcome to Www.111cn.net "; $fh = fopen ($filename, "a"); W writes a append write from the beginning Echo fwrite ($fh, $word); Fclose ($FH); ?>

In the above example, Echo fwrite () shows a number that represents the length of the string