Removing all script tags from html with JS Regular Expression

i want to strip script tags out of this html at pastebin

http://pastebin.com/mdxygM0a

I tried using the below regular expression

html.replace(/<script.*>.*<\/script>/ims, " ")

But it does not remove all script tags in the html. It only removes in-line scripts. Please i need a regex that can remove all script tags(in-line and multi-line). It would be highly appreciated if a test is carried out on my sample http://pastebin.com/mdxygM0a

Thanks

Answers:

Answer

Attempting to remove HTML markup using a regular expression is problematic. You don't know what's in there as script or attribute values. One way is to insert it as the innerHTML of a div, remove any script elements and return the innerHTML, e.g.

  function stripScripts(s) {
    var div = document.createElement('div');
    div.innerHTML = s;
    var scripts = div.getElementsByTagName('script');
    var i = scripts.length;
    while (i--) {
      scripts[i].parentNode.removeChild(scripts[i]);
    }
    return div.innerHTML;
  }

alert(
 stripScripts('<span><script type="text/javascript">alert(\'foo\');<\/script><\/span>')
);

Note that at present, browsers will not execute the script if inserted using the innerHTML property, and likely never will especially as the element is not added to the document.

Answer

jQuery uses a regex to remove script tags in some cases and I'm pretty sure its devs had a damn good reason to do so. Probably some browser does execute scripts when inserting them using innerHTML.

Here's the regex:

/<script\b[^<]*(?:(?!<\/script>)<[^<]*)*<\/script>/gi

And before people start crying "but regexes for HTML are evil": Yes, they are - but for script tags they are safe because of the special behaviour - a <script> section may not contain </script> at all unless it should end at this position. So matching it with a regex is easily possible. However, from a quick look the regex above does not account for trailing whitespace inside the closing tag so you'd have to test if </script    etc. will still work.

Answer

Regexes are beatable, but if you have a string version of HTML that you don't want to inject into a DOM, they may be the best approach. You may want to put it in a loop to handle something like:

<scr<script>Ha!</script>ipt> alert(document.cookie);</script>

Here's what I did, using the jquery regex from above:

var SCRIPT_REGEX = /<script\b[^<]*(?:(?!<\/script>)<[^<]*)*<\/script>/gi;
while (SCRIPT_REGEX.test(text)) {
    text = text.replace(SCRIPT_REGEX, "");
}
Answer

Whenever you have to resort to Regex based script tag cleanup. At least add a white-space to the closing tag in the form of

</script\s*>

Otherwise things like

<script>alert(666)</script   >

would remain since trailing spaces after tagnames are valid.

Answer

Why not using jQuery.parseHTML() http://api.jquery.com/jquery.parsehtml/?

Answer

In my case, I needed a requirement to parse out the page title AND and have all the other goodness of jQuery, minus it firing scripts. Here is my solution that seems to work.

        $.get('/somepage.htm', function (data) {
            // excluded code to extract title for simplicity
            var bodySI = data.indexOf('<body>') + '<body>'.length,
                bodyEI = data.indexOf('</body>'),
                body = data.substr(bodySI, bodyEI - bodySI),
                $body;

            body = body.replace(/<script[^>]*>/gi, ' <!-- ');
            body = body.replace(/<\/script>/gi, ' --> ');

            //console.log(body);

            $body = $('<div>').html(body);
            console.log($body.html());
        });

This kind of shortcuts worries about script because you are not trying to remove out the script tags and content, instead you are replacing them with comments rendering schemes to break them useless as you would have comments delimiting your script declarations.

Let me know if that still presents a problem as it will help me too.

Answer

If you want to remove all JavaScript code from some HTML text, then removing <script> tags isn't enough, because JavaScript can still live in "onclick", "onerror", "href" and other attributes.

Try out this npm module which handles all of this: https://www.npmjs.com/package/strip-js

Answer

Here are a variety of shell scripts you can use to strip out different elements.

# doctype
find . -regex ".*\.\(html\|py\)$" -type f -exec sed -i "s/<\!DOCTYPE\s\+html[^>]*>/<\!DOCTYPE html>/gi" {} \;

# meta charset
find . -regex ".*\.\(html\|py\)$" -type f -exec sed -i "s/<meta[^>]*content=[\"'][^\"']*utf-8[\"'][^>]*>/<meta charset=\"utf-8\">/gi" {} \;

# script text/javascript
find . -regex ".*\.\(html\|py\)$" -type f -exec sed -i "s/\(<script[^>]*\)\(\stype=[\"']text\/javascript[\"']\)\(\s\?[^>]*>\)/\1\3/gi" {} \;

# style text/css
find . -regex ".*\.\(html\|py\)$" -type f -exec sed -i "s/\(<style[^>]*\)\(\stype=[\"']text\/css[\"']\)\(\s\?[^>]*>\)/\1\3/gi" {} \;

# html xmlns
find . -regex ".*\.\(html\|py\)$" -type f -exec sed -i "s/\(<html[^>]*\)\(\sxmlns=[\"'][^\"']*[\"']\)\(\s\?[^>]*>\)/\1\3/gi" {} \;

# html xml:lang
find . -regex ".*\.\(html\|py\)$" -type f -exec sed -i "s/\(<html[^>]*\)\(\sxml:lang=[\"'][^\"']*[\"']\)\(\s\?[^>]*>\)/\1\3/gi" {} \;
Answer

You can try

$("your_div_id").remove();  

or

 $("your_div_id").html(""); 
Answer

This Regex should work too:

<script(?:(?!\/\/)(?!\/\*)[^'"]|"(?:\\.|[^"\\])*"|'(?:\\.|[^'\\])*'|\/\/.*(?:\n)|\/\*(?:(?:.|\s))*?\*\/)*?<\/script>

It even allows to have "problematic" variable strings like these inside:

<script type="text/javascript">
   var test1 = "</script>";
   var test2 = '\'</script>';
   var test1 = "\"</script>";
   var test1 = "<script>\"";
   var test2 = '<scr\'ipt>';
   /* </script> */
   // </script>
   /* ' */
   // var foo=" '
</script>

It seams that jQuery and Prototype fail on these ones...

Edit July 31 '17: Added a) non-capturing groups for better performance (and no empty groups) and b) support for JavaScript comments.

Answer

/(?:(?!</s\w)<[^<])</s\w*/gi; - Removes any sequence in any combination with

Answer

Try this:

var text = text.replace(/<script[^>]*>(?:(?!<\/script>)[^])*<\/script>/g, "")

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