php自定义函数转换html标签示例

<?php
/*
* Created on 2016-9-29
*
*/
$orig = "I'll \"walk\" the <b>dog</b> now";
$a = htmlentities($orig);
$b = html_entity_decode($a);
echo $a; // I'll &amp;quot;walk&amp;quot; the &amp;lt;b&amp;gt;dog&amp;lt;/b&amp;gt; now
echo $b; // I'll "walk" the <b>dog</b> now
// For users prior to PHP 4.3.0 you may do this:
function unhtmlentities($string)
{
  // replace numeric entities
  $string = preg_replace('~&amp;#x([0-9a-f]+);~ei', 'chr(hexdec("\\1"))', $string);
  $string = preg_replace('~&amp;#([0-9]+);~e', 'chr("\\1")', $string);
  // replace literal entities
  $trans_tbl = get_html_translation_table(HTML_ENTITIES);
  $trans_tbl = array_flip($trans_tbl);
  return strtr($string, $trans_tbl);
}
$c = unhtmlentities($a);
echo $c; // I'll "walk" the <b>dog</b> now
?>