PHP 清理字符串中所有无用标签

function Bing_string_cleanr( $string ){
 $string = trim( $string );
 $string = strip_tags( $string );
 $string = htmlspecialchars( $string, ENT_QUOTES, 'UTF-8' );
 $string = str_replace( "n", "", $string );
 $string = trim( $string );
 return $string;
}

<?php
$str = " This line containstliberal rn use of whitespace.nn";

// First remove the leading/trailing whitespace
//去掉开始和结束的空白
$str = trim($str);

// Now remove any doubled-up whitespace
//去掉跟随别的挤在一块的空白
$str = preg_replace('/s(?=s)/', '', $str);

// Finally, replace any non-space whitespace, with a space
//最后，去掉非space 的空白，用一个空格代替
$str = preg_replace('/[nrt]/', ' ', $str);

// Echo out: 'This line contains liberal use of whitespace.'
echo "

{$str}