» Javascript equivalent for PHP's strip_tags

PHP to Javascript Project: php.js

php.jsThis article is part of the 'Porting PHP to Javascript' Project, which aims to decrease the gap between developing for PHP & Javascript.

A lot of people are familiar with PHP's functions, and though Javascript functions are often quite similar, some functions may be missing or addressed differently. The Javascript implementations should be as compliant with the PHP versions as possible, a good indication is that the PHP function manual could also apply to the Javascript version.

Porting crucial PHP functions to Javascript can be fun & useful. Currently some PHP functions have been added, but readers are encouraged to contribute and improve functions by adding comments. Eventually the goal is to save all the functions in one php.js file and make it publicly available for your coding pleasure.

If you choose to contribute, let me know how you want to be credited in the function's comments. You may also want to subscribe to RSS so you receive updates whenever new functions are posted.

This is a Javascript version of the PHP function: strip_tags.

PHP strip_tags

Description

strip_tags - Strip HTML and PHP tags from a string

string strip_tags( string str [, string allowable_tags] )

This function tries to return a string with all HTML and PHP tags stripped from a given str.It uses the same tag stripping state machine as the fgetss() function.

Parameters

  • str

    The input string.

  • allowable_tags

    You can use the optional second parameter to specify tags which should not be stripped.

    Note: HTML comments and PHP tags are also stripped. This is hardcoded and can not be changed with allowable_tags .

Return Values

Returns the stripped string.

See Also

Javascript strip_tags

Source

This is the main source of the Javascript version of PHP's strip_tags

function strip_tags(str, allowed_tags) {
    // http://kevin.vanzonneveld.net
    // +   original by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +   improved by: Luke Godfrey
    // *     example 1: strip_tags('<p>Kevin</p> <br /><b>van</b> <i>Zonneveld</i>', '<i>,<b>');
    // *     returns 1: 'Kevin <b>van</b> <i>Zonneveld</i>'
    // *     example 2: strip_tags('<p>Kevin <img src="someimage.png" onmouseover="someFunction()">van <i>Zonneveld</i></p>');
    // *     returns 2: 'Kevin van Zonneveld'
    
    var key = '', tag = '';
    var matches = allowed_array = [];
    var allowed_keys = {};
    
    // Build allowes tags associative array
    if (allowed_tags) {
        allowed_tags  = allowed_tags.replace(/[\<\> ]+/g, '');;
        allowed_array = allowed_tags.split(',');
        
        for (key in allowed_array) {
            tag = allowed_array[key];
            allowed_keys['<' + tag + '>']   = true;
            allowed_keys['<' + tag + ' />'] = true;
            allowed_keys['</' + tag + '>']  = true;
        }
    }
    
    // Match tags
    matches = str.match(/(<\/?[^>]+>)/gi);
    
    // Is tag not in allowed list? Remove from str! 
    for (key in matches) {
        // IE7 Hack
        if (!isNaN(key)) {
            tag = matches[key].toString();
            if (!allowed_keys[tag]) {
                // Looks like this is
                // reg = RegExp(tag, 'g');
                // str = str.replace(reg, '');
                str = str.replace(tag, "");
            }
        }
    }
    
    return str;
}

Examples

Currently there are 2 examples

Example 1

This is how you could call strip_tags()
strip_tags('<p>Kevin</p> 
<b>van</b> <i>Zonneveld</i>', '<i>,<b>');
And that would return
'Kevin <b>van</b> <i>Zonneveld</i>'

Example 2

This is how you could call strip_tags()
strip_tags('<p>Kevin <img src="someimage.png" onmouseover="someFunction()">van <i>Zonneveld</i></p>');
And that would return
'Kevin van Zonneveld'

More about this Project

Download php.js

To easily include it in your code, every function currently available is stored in

Normal

Namespaced What is 'namespaced?'

To download use Right click, Save Link As
Generally the best way is to use a minified version and gzip it



Testing the functions

The number of functions is growing fast and so it becomes hard to maintain quality.

To defeat that danger of bad code, syntax errors, etc, I've added a new feature: php.js tester.

It is an automatically generated page that includes ALL functions in your browser, and then extracts specific testing information from each function's comments. This info is then used to run the function, and the return value is compared to a predefined one.

If you want, go check it out.


Credits

Respect & awards go to everybody who has contributed in some way so far:

medalmedalMichael White (link) for contributing to:
 array_count_values, get_included_files, include, include_once, require, require_once, md5, number_format, parse_str, printf, sha1, sprintf, str_pad, strnatcmp, http_build_query, floatval, is_object, print_r
spacemedal_argos for contributing to:
 array_fill, array_pad, array_product, array_rand, compact, count, range, abs, defined, ip2long, long2ip, implode, strcmp, ucwords
spacemedalJonas Raoni Soares Silva (link) for contributing to:
 shuffle, abs, setcookie, number_format, number_format, soundex, str_repeat, str_replace, str_rot13, ucwords, wordwrap, wordwrap
spacemedalLegaev Andrey for contributing to:
 end, reset, file, file_get_contents, function_exists, include, include_once, http_build_query, is_array, is_object
spacemedalAtes Goral (link) for contributing to:
 array_change_key_case, array_count_values, array_diff_key, get_class, preg_quote, addslashes, count_chars, str_rot13, stripslashes
spacemedalPhilip Peterson for contributing to:
 sizeof, round, echo, nl2br, str_replace, strchr, urldecode, urlencode, var_export
spacemedalMartijn Wieringa for contributing to:
 array_shift, array_unshift, str_ireplace, str_split, strcasecmp, stripos, strnatcmp, substr
spacemedalWebtoolkit.info (link) for contributing to:
 crc32, md5, sha1, utf8_decode, utf8_encode
 
spacemedalCarlos R. L. Rodrigues (link) for contributing to:
 array_chunk, array_unique, date, levenshtein
spacemedalAsh Searle (link) for contributing to:
 basename, printf, sprintf
spacemedalErkekjetter for contributing to:
 ltrim, rtrim, trim
spacemedalGeekFG (link) for contributing to:
 krsort, ksort, time
spacemedalJohnny Mast (link) for contributing to:
 array_walk, array_walk_recursive, create_function
spacemedald3x for contributing to:
 array, explode, unserialize
spacemedalmarrtins for contributing to:
 array_change_key_case, addslashes, stripslashes
spacemedalAlfonso Jimenez (link) for contributing to:
 array_reduce, strpbrk
spacemedalAman Gupta for contributing to:
 base64_decode, utf8_decode
spacemedalArpad Ray (mailto:arpad@php.net) for contributing to:
 serialize, unserialize
spacemedalKarol Kowalski for contributing to:
 array_reverse, abs
spacemedalMirek Slugen for contributing to:
 htmlspecialchars, htmlspecialchars_decode
spacemedalOnno Marsman for contributing to:
 addslashes, isset
spacemedalThunder.m for contributing to:
 base64_decode, base64_encode
spacemedalTyler Akins (link) for contributing to:
 base64_decode, base64_encode
spacemedalmdsjack (link) for contributing to:
 include, trim
spacemedalAlex for contributing to:
 is_int
spacemedalAlexander Ermolaev (link) for contributing to:
 trim
spacemedalAllan Jensen (link) for contributing to:
 number_format
spacemedalAndrea Giammarchi (link) for contributing to:
 array_map
spacemedalArno for contributing to:
 htmlspecialchars
spacemedalBayron Guevara for contributing to:
 base64_encode
spacemedalBen Bryan for contributing to:
 print_r
spacemedalBenjamin Lupton for contributing to:
 number_format
spacemedalBrad Touesnard for contributing to:
 date
spacemedalBrett Zamir for contributing to:
 str_split
spacemedalCagri Ekin for contributing to:
 parse_str
spacemedalCord for contributing to:
 is_array
spacemedalDavid for contributing to:
 is_numeric
spacemedalDavid James for contributing to:
 get_class
spacemedalDxGx for contributing to:
 trim
spacemedalFGFEmperor for contributing to:
 mktime
spacemedalFelix Geisendoerfer (link) for contributing to:
 array_key_exists
spacemedalFremyCompany for contributing to:
 isset
spacemedalGabriel Paderni for contributing to:
 str_replace
spacemedalHoward Yeend for contributing to:
 number_format
spacemedalJ A R for contributing to:
 end
spacemedalJack for contributing to:
 trim
spacemedalLeslie Hoare for contributing to:
 rand
spacemedalLincoln Ramsay for contributing to:
 basename
spacemedalLuke Godfrey for contributing to:
 strip_tags
spacemedalMeEtc (link) for contributing to:
 date
spacemedalMick@el for contributing to:
 stripslashes
spacemedalNate for contributing to:
 addslashes
spacemedalNathan for contributing to:
 htmlspecialchars
spacemedalNick Callen for contributing to:
 wordwrap
spacemedalOzh for contributing to:
 dirname
spacemedalPedro Tainha (link) for contributing to:
 unserialize
spacemedalPeter-Paul Koch (link) for contributing to:
 date
spacemedalPhilippe Baumann for contributing to:
 empty
spacemedalPyerre for contributing to:
 checkdate
spacemedalSakimori for contributing to:
 strlen
spacemedalSanjoy Roy for contributing to:
 array_diff
spacemedalSimon Willison (link) for contributing to:
 str_replace
spacemedalSteve Clay for contributing to:
 function_exists
spacemedalSteve Hilder for contributing to:
 strcmp
spacemedalSteven Levithan (link) for contributing to:
 trim
spacemedalT0bsn for contributing to:
 crc32
spacemedalThiago Mata (link) for contributing to:
 call_user_func_array
spacemedalTim Wiel for contributing to:
 date
spacemedalXoraX (link) for contributing to:
 dirname
spacemedalYannoo for contributing to:
 mktime
spacemedalbaris ozdil for contributing to:
 mktime
spacemedalbooeyOH for contributing to:
 preg_quote
spacemedaldjmix for contributing to:
 basename
spacemedaldptr1988 for contributing to:
 unserialize
spacemedalduncan for contributing to:
 array_unique
spacemedalecho is bad for contributing to:
 echo
spacemedalgabriel paderni for contributing to:
 mktime
spacemedalger for contributing to:
 html_entity_decode
spacemedalgorthaur for contributing to:
 strcmp
spacemedaljakes for contributing to:
 mktime
spacemedaljohn (link) for contributing to:
 html_entity_decode
spacemedaljohnrembo for contributing to:
 var_export
spacemedalkenneth for contributing to:
 explode
spacemedalloonquawl for contributing to:
 htmlspecialchars_decode
spacemedalmetjay for contributing to:
 time
spacemedalpenutbutterjelly for contributing to:
 str_ireplace
spacemedalsankai for contributing to:
 array_count_values
spacemedalsowberry for contributing to:
 utf8_encode
spacemedalstensi for contributing to:
 intval

Your name here?

Contributing is as easy as adding a comment with better code, or code for a new function.
Any contribution leading to improvement will directly get your name & link here.


Coming Project features

Project features that we are currently working on:

  • Versioning. Individual functions are versioned, but the entire library should be versioned as well.
  • Light. A lightweight version of php.js should be made available with only common functions in it.
  • Site. A place for PHP.JS of it's own. You can track our lame attempts at phpjs.org (not hyperlinked deliberately). If there are any CakePHP developers out there who would like to contribute, contact me.
  • Testsuite. A better test-suite that can be ran locally so developers can easily test before commiting. Also the testing itself should be more thorough.

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tags: programming, php, javascript
category: Programming - Javascript - PHP equivalents
read: 2,754 times

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Comments

#6. Kevin (link) on 18 July 2008

Member avatar: Kevin@ Steven Richards: I've made what I think is the right change. Does this work okay?

#5. Steven Richards on 09 July 2008

Default avatar:Steven RichardsThe strip_tags() function appears to be broken in IE7. Upon detecting an opening tag, it completely removes ALL output. The same behavior appears on the test page on this site. It appears that in IE, the match() function returns a copy of the input string and a couple other extraneous values on a successful match, causing the entire string to be replaced by the first matched key (the original input). To fix, I added this ugly piece of work inside the key loop:

if (key == '0' || Number(key.toString()))
{
// replacement
}

#4. Mohammed on 20 June 2008

Default avatar:MohammedThanks!

#3. Rauan on 01 June 2008

Default avatar:RauanWow. Thanks, Kevin. That's the very important feature. :)

#2. Kevin (link) on 31 May 2008

Member avatar: Kevin@ Rauan: PHP.JS is by no means a full PHP implementation in Javascript. But thanks for pointing this out, I've added the functionality

#1. Rauan on 23 May 2008

Default avatar:RauanOk, that's great... But where is exception in regex for allowed_tags?