JavaScript strip_tags and stripslashes

stripslashes()

The strip_tags(), and stripslashes() functions are generally known and used in PHP. These functions are useful when working with strings that contains HTML code, but JavaScript doesn't have such functions.
Here's these functions for JavaScript.

strip_tags

strip_tags(string, allow) - returns a string with HTML and PHP tags stripped from a given string. HTML comments are also stripped.
The allow parameter is optional, and represents a string with allowable tags, which should not be stripped (a string like: '<b><i><u>').
Code:

function strip_tags(str, allow){
 // making sure the allow arg is a string containing only tags in lowercase (<a><b><c>)
 allow = (((allow || '') + '').toLowerCase().match(/<[a-z][a-z0-9]*>/g) || []).join('');

 var tags = /<\/?([a-z][a-z0-9]*)\b[^>]*>/gi;
 var commentsAndPhpTags = /<!--[\s\S]*?-->|<\?(?:php)?[\s\S]*?\?>/gi;
 return str.replace(commentsAndPhpTags, '').replace(tags, function ($0, $1) {
 return allow.indexOf('<' + $1.toLowerCase() + '>') > -1 ? $0 :'';
 });
}

Example:

<div id='sresult'>#sresult</div>

<script>
function strip_tags(str, allow){
 // making sure the allow arg is a string containing only tags in lowercase (<a><b><c>)
 allow = (((allow || '') + '').toLowerCase().match(/<[a-z][a-z0-9]*>/g) || []).join('');

 var tags = /<\/?([a-z][a-z0-9]*)\b[^>]*>/gi;
 var commentsAndPhpTags = /<!--[\s\S]*?-->|<\?(?:php)?[\s\S]*?\?>/gi;
 return str.replace(commentsAndPhpTags, '').replace(tags, function ($0, $1) {
 return allow.indexOf('<' + $1.toLowerCase() + '>') > -1 ? $0 :'';
 });
}

var str = '<p>Test paragraph.</p><!-- Comment --> <a href="https://coursesweb.net/">CoursesWeb.net</a>.<br>New line: <b>Bold</b>, and <u>Underline</u>. An opening Span tag: <span>*';

var str1 = strip_tags(str); // removes all tags
var str2 = strip_tags(str, '<b><u>'); // keeps <b> and <u> tags

// adds str1 and str2 in webpage
document.getElementById('sresult').innerHTML = 'str1: '+ str1+ '<br/>str2: '+ str2;
</script>

Result:

str1: Test paragraph. CoursesWeb.net.New line: Bold, and Underline. An opening Span tag: *
str2: Test paragraph. CoursesWeb.net.New line: Bold, and Underline. An opening Span tag: *

stripslashes

stripslashes() - un-quotes a quoted string. Returns a string with backslashes stripped off. (\', and \' become ' and ') Double backslashes (\\) are made into a single backslash (\).
Code:

function stripslashes(str) {
 return str.replace(/\\'/g,'\'').replace(/\"/g,'"').replace(/\\\\/g,'\\').replace(/\\0/g,'\0');
}

Example:

// stripslashes
function stripslashes(str) {
 return str.replace(/\\'/g,'\'').replace(/\"/g,'"').replace(/\\\\/g,'\\').replace(/\\0/g,'\0');
}

var str = 'String with \"backslashes\", \\ coursesweb.net/';
str = stripslashes(str);
str = stripslashes(str);

document.write(str); // String with 'backslashes', \ coursesweb.net/

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Daily Test with Code Example

HTML

CSS

JavaScript

PHP-MySQL

Which tag is used to add lists into <ul> and <ol> elements?

<ul>
 <li>http://coursesweb.net/html/</li>
 <li>http://coursesweb.net/css/</li>
</ul>

Which value of the "display" property creates a block box for the content and ads a bullet marker?

block list-item inline-block

.some_class {
  display: list-item;
}

Which instruction converts a JavaScript object into a JSON string.

JSON.parse() JSON.stringify eval()

var obj = {
 "courses": ["php", "javascript", "ajax"]
};
var jsonstr = JSON.stringify(obj);
alert(jsonstr);    // {"courses":["php","javascript","ajax"]}

Indicate the PHP class used to work with HTML and XML content in PHP.

stdClass PDO DOMDocument

$strhtml = '<body><div id="dv1">CoursesWeb.net</div></body>';
$dochtml = new DOMDocument();
$dochtml->loadHTML($strhtml);
$elm = $dochtml->getElementById("dv1");
echo $elm->nodeValue;    // CoursesWeb.net