Web development methods for filtering JavaScript and HTML

JavaScript filtering methods:

The first scenario: Use the Htmlspecialchars function to convert special characters and use the NL2BR function to insert some necessary <br/> tags.

1 $comment = <<<eof  2 <script type= "Text/javascript" >  3  while (true) {  4     alert (' I play! ');   5 }  6 </script>  7 EOF;  // If $comment is a comment   8 // filter JavaScript code   9 Echo $comment;

The output is:

&lt;script type=&quot;text/javascript&quot;&gt;<br/> while (true) {<br/ >    alert (' I play! '); <br/>}<br/>&lt;/script&gt;

The second option: Remove all the <script...>,</script> from the comment content.

1 // get rid  of all the <script...>,</script> in the comments

The output is:

 while (true) {      alert (' I play! ');  }  

HTML Filtering methods:

The first option: to escape the symbol <>, or delete it directly.

1 $comment = preg_replace ("/<[\/\!") *? [^<>]*?>/si ",", $comment);  

The second scenario: Use the Strip_tags () function.

1 <? PHP 2 Echo strip_tags ("Hello <b>world!</b>"); 3 ?>

Web development methods for filtering JavaScript and HTML