Is there an easy way to take a string of html in JavaScript and strip out the html?
This question is related to
javascript
html
string
simple 2 line jquery to strip the html.
var content = "<p>checking the html source </p><p>
</p><p>with </p><p>all</p><p>the html </p><p>content</p>";
var text = $(content).text();//It gets you the plain text
console.log(text);//check the data in your console
cj("#text_area_id").val(text);//set your content to text area using text_area_id
from CSS tricks:
https://css-tricks.com/snippets/javascript/strip-html-tags-in-javascript/
const originalString = `
<div>
<p>Hey that's <span>somthing</span></p>
</div>
`;
const strippedString = originalString.replace(/(<([^>]+)>)/gi, "");
console.log(strippedString);Using Jquery:
function stripTags() {
return $('<p></p>').html(textToEscape).text()
}
The accepted answer works fine mostly, however in IE if the html string is null you get the "null" (instead of ''). Fixed:
function strip(html)
{
if (html == null) return "";
var tmp = document.createElement("DIV");
tmp.innerHTML = html;
return tmp.textContent || tmp.innerText || "";
}
I altered Jibberboy2000's answer to include several <BR /> tag formats, remove everything inside <SCRIPT> and <STYLE> tags, format the resulting HTML by removing multiple line breaks and spaces and convert some HTML-encoded code into normal. After some testing it appears that you can convert most of full web pages into simple text where page title and content are retained.
In the simple example,
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<!--comment-->
<head>
<title>This is my title</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style>
body {margin-top: 15px;}
a { color: #D80C1F; font-weight:bold; text-decoration:none; }
</style>
</head>
<body>
<center>
This string has <i>html</i> code i want to <b>remove</b><br>
In this line <a href="http://www.bbc.co.uk">BBC</a> with link is mentioned.<br/>Now back to "normal text" and stuff using <html encoding>
</center>
</body>
</html>
becomes
This is my title
This string has html code i want to remove
In this line BBC (http://www.bbc.co.uk) with link is mentioned.
Now back to "normal text" and stuff using
The JavaScript function and test page look this:
function convertHtmlToText() {
var inputText = document.getElementById("input").value;
var returnText = "" + inputText;
//-- remove BR tags and replace them with line break
returnText=returnText.replace(/<br>/gi, "\n");
returnText=returnText.replace(/<br\s\/>/gi, "\n");
returnText=returnText.replace(/<br\/>/gi, "\n");
//-- remove P and A tags but preserve what's inside of them
returnText=returnText.replace(/<p.*>/gi, "\n");
returnText=returnText.replace(/<a.*href="(.*?)".*>(.*?)<\/a>/gi, " $2 ($1)");
//-- remove all inside SCRIPT and STYLE tags
returnText=returnText.replace(/<script.*>[\w\W]{1,}(.*?)[\w\W]{1,}<\/script>/gi, "");
returnText=returnText.replace(/<style.*>[\w\W]{1,}(.*?)[\w\W]{1,}<\/style>/gi, "");
//-- remove all else
returnText=returnText.replace(/<(?:.|\s)*?>/g, "");
//-- get rid of more than 2 multiple line breaks:
returnText=returnText.replace(/(?:(?:\r\n|\r|\n)\s*){2,}/gim, "\n\n");
//-- get rid of more than 2 spaces:
returnText = returnText.replace(/ +(?= )/g,'');
//-- get rid of html-encoded characters:
returnText=returnText.replace(/ /gi," ");
returnText=returnText.replace(/&/gi,"&");
returnText=returnText.replace(/"/gi,'"');
returnText=returnText.replace(/</gi,'<');
returnText=returnText.replace(/>/gi,'>');
//-- return
document.getElementById("output").value = returnText;
}
It was used with this HTML:
<textarea id="input" style="width: 400px; height: 300px;"></textarea><br />
<button onclick="convertHtmlToText()">CONVERT</button><br />
<textarea id="output" style="width: 400px; height: 300px;"></textarea><br />
method 1:
function cleanHTML(str){
str.replace(/<(?<=<)(.*?)(?=>)>/g, '<$1>');
}
function uncleanHTML(str){
str.replace(/<(?<=<)(.*?)(?=>)>/g, '<$1>');
}
method 2:
function cleanHTML(str){
str.replace(/</g, '<').replace(/>/g, '>');
}
function uncleanHTML(str){
str.replace(/</g, '<').replace(/>/g, '>');
}
also, don't forget if the user happens to post a math comment (ex: 1 < 2), you don't want to strip the whole comment. The browser (only tested chrome) doesn't run unicode as html tags. if you replace all < with < everyware in the string, the unicode will display < as text without running any html. I recommend method 2. jquery also works well $('#element').text();
Here's a version which sorta addresses @MikeSamuel's security concern:
function strip(html)
{
try {
var doc = document.implementation.createDocument('http://www.w3.org/1999/xhtml', 'html', null);
doc.documentElement.innerHTML = html;
return doc.documentElement.textContent||doc.documentElement.innerText;
} catch(e) {
return "";
}
}
Note, it will return an empty string if the HTML markup isn't valid XML (aka, tags must be closed and attributes must be quoted). This isn't ideal, but does avoid the issue of having the security exploit potential.
If not having valid XML markup is a requirement for you, you could try using:
var doc = document.implementation.createHTMLDocument("");
but that isn't a perfect solution either for other reasons.
I have created a working regular expression myself:
str=str.replace(/(<\?[a-z]*(\s[^>]*)?\?(>|$)|<!\[[a-z]*\[|\]\]>|<!DOCTYPE[^>]*?(>|$)|<!--[\s\S]*?(-->|$)|<[a-z?!\/]([a-z0-9_:.])*(\s[^>]*)?(>|$))/gi, '');
var text = html.replace(/<\/?("[^"]*"|'[^']*'|[^>])*(>|$)/g, "");
This is a regex version, which is more resilient to malformed HTML, like:
Unclosed tags
Some text <img
"<", ">" inside tag attributes
Some text <img alt="x > y">
Newlines
Some <a
href="http://google.com">
The code
var html = '<br>This <img alt="a>b" \r\n src="a_b.gif" />is > \nmy<>< > <a>"text"</a'
var text = html.replace(/<\/?("[^"]*"|'[^']*'|[^>])*(>|$)/g, "");
For easier solution, try this => https://css-tricks.com/snippets/javascript/strip-html-tags-in-javascript/
var StrippedString = OriginalString.replace(/(<([^>]+)>)/ig,"");
An improvement to the accepted answer.
function strip(html)
{
var tmp = document.implementation.createHTMLDocument("New").body;
tmp.innerHTML = html;
return tmp.textContent || tmp.innerText || "";
}
This way something running like this will do no harm:
strip("<img onerror='alert(\"could run arbitrary JS here\")' src=bogus>")
Firefox, Chromium and Explorer 9+ are safe. Opera Presto is still vulnerable. Also images mentioned in the strings are not downloaded in Chromium and Firefox saving http requests.
A lot of people have answered this already, but I thought it might be useful to share the function I wrote that strips HTML tags from a string but allows you to include an array of tags that you do not want stripped. It's pretty short and has been working nicely for me.
function removeTags(string, array){
return array ? string.split("<").filter(function(val){ return f(array, val); }).map(function(val){ return f(array, val); }).join("") : string.split("<").map(function(d){ return d.split(">").pop(); }).join("");
function f(array, value){
return array.map(function(d){ return value.includes(d + ">"); }).indexOf(true) != -1 ? "<" + value : value.split(">")[1];
}
}
var x = "<span><i>Hello</i> <b>world</b>!</span>";
console.log(removeTags(x)); // Hello world!
console.log(removeTags(x, ["span", "i"])); // <span><i>Hello</i> world!</span>
function stripHTML(my_string){
var charArr = my_string.split(''),
resultArr = [],
htmlZone = 0,
quoteZone = 0;
for( x=0; x < charArr.length; x++ ){
switch( charArr[x] + htmlZone + quoteZone ){
case "<00" : htmlZone = 1;break;
case ">10" : htmlZone = 0;resultArr.push(' ');break;
case '"10' : quoteZone = 1;break;
case "'10" : quoteZone = 2;break;
case '"11' :
case "'12" : quoteZone = 0;break;
default : if(!htmlZone){ resultArr.push(charArr[x]); }
}
}
return resultArr.join('');
}
Accounts for > inside attributes and <img onerror="javascript"> in newly created dom elements.
usage:
clean_string = stripHTML("string with <html> in it")
demo:
https://jsfiddle.net/gaby_de_wilde/pqayphzd/
demo of top answer doing the terrible things:
(function($){
$.html2text = function(html) {
if($('#scratch_pad').length === 0) {
$('<div id="lh_scratch"></div>').appendTo('body');
}
return $('#scratch_pad').html(html).text();
};
})(jQuery);
Define this as a jquery plugin and use it like as follows:
$.html2text(htmlContent);
I made some modifications to original Jibberboy2000 script Hope it'll be usefull for someone
str = '**ANY HTML CONTENT HERE**';
str=str.replace(/<\s*br\/*>/gi, "\n");
str=str.replace(/<\s*a.*href="(.*?)".*>(.*?)<\/a>/gi, " $2 (Link->$1) ");
str=str.replace(/<\s*\/*.+?>/ig, "\n");
str=str.replace(/ {2,}/gi, " ");
str=str.replace(/\n+\s*/gi, "\n\n");
Below code allows you to retain some html tags while stripping all others
function strip_tags(input, allowed) {
allowed = (((allowed || '') + '')
.toLowerCase()
.match(/<[a-z][a-z0-9]*>/g) || [])
.join(''); // making sure the allowed arg is a string containing only tags in lowercase (<a><b><c>)
var tags = /<\/?([a-z][a-z0-9]*)\b[^>]*>/gi,
commentsAndPhpTags = /<!--[\s\S]*?-->|<\?(?:php)?[\s\S]*?\?>/gi;
return input.replace(commentsAndPhpTags, '')
.replace(tags, function($0, $1) {
return allowed.indexOf('<' + $1.toLowerCase() + '>') > -1 ? $0 : '';
});
}
I think the easiest way is to just use Regular Expressions as someone mentioned above. Although there's no reason to use a bunch of them. Try:
stringWithHTML = stringWithHTML.replace(/<\/?[a-z][a-z0-9]*[^<>]*>/ig, "");
With jQuery you can simply retrieving it by using
$('#elementID').text()
Another, admittedly less elegant solution than nickf's or Shog9's, would be to recursively walk the DOM starting at the <body> tag and append each text node.
var bodyContent = document.getElementsByTagName('body')[0];
var result = appendTextNodes(bodyContent);
function appendTextNodes(element) {
var text = '';
// Loop through the childNodes of the passed in element
for (var i = 0, len = element.childNodes.length; i < len; i++) {
// Get a reference to the current child
var node = element.childNodes[i];
// Append the node's value if it's a text node
if (node.nodeType == 3) {
text += node.nodeValue;
}
// Recurse through the node's children, if there are any
if (node.childNodes.length > 0) {
appendTextNodes(node);
}
}
// Return the final result
return text;
}
As an extension to the jQuery method, if your string might not contain HTML (eg if you are trying to remove HTML from a form field)
jQuery(html).text();
will return an empty string if there is no HTML
Use:
jQuery('<p>' + html + '</p>').text();
instead.
Update:
As has been pointed out in the comments, in some circumstances this solution will execute javascript contained within html if the value of html could be influenced by an attacker, use a different solution.
This should do the work on any Javascript environment (NodeJS included).
const text = `
<html lang="en">
<head>
<style type="text/css">*{color:red}</style>
<script>alert('hello')</script>
</head>
<body><b>This is some text</b><br/><body>
</html>`;
// Remove style tags and content
text.replace(/<style[^>]*>.*<\/style>/gm, '')
// Remove script tags and content
.replace(/<script[^>]*>.*<\/script>/gm, '')
// Remove all opening, closing and orphan HTML tags
.replace(/<[^>]+>/gm, '')
// Remove leading spaces and repeated CR/LF
.replace(/([\r\n]+ +)+/gm, '');
Simplest way:
jQuery(html).text();
That retrieves all the text from a string of html.
function strip_html_tags(str)
{
if ((str===null) || (str===''))
return false;
else
str = str.toString();
return str.replace(/<[^>]*>/g, '');
}
If you want to keep the links and the structure of the content (h1, h2, etc) then you should check out TextVersionJS You can use it with any HTML, although it was created to convert an HTML email to plain text.
The usage is very simple. For example in node.js:
var createTextVersion = require("textversionjs");
var yourHtml = "<h1>Your HTML</h1><ul><li>goes</li><li>here.</li></ul>";
var textVersion = createTextVersion(yourHtml);
Or in the browser with pure js:
<script src="textversion.js"></script>
<script>
var yourHtml = "<h1>Your HTML</h1><ul><li>goes</li><li>here.</li></ul>";
var textVersion = createTextVersion(yourHtml);
</script>
It also works with require.js:
define(["textversionjs"], function(createTextVersion) {
var yourHtml = "<h1>Your HTML</h1><ul><li>goes</li><li>here.</li></ul>";
var textVersion = createTextVersion(yourHtml);
});
I just needed to strip out the <a> tags and replace them with the text of the link.
This seems to work great.
htmlContent= htmlContent.replace(/<a.*href="(.*?)">/g, '');
htmlContent= htmlContent.replace(/<\/a>/g, '');
I would like to share an edited version of the Shog9's approved answer.
As Mike Samuel pointed with a comment, that function can execute inline javascript codes.
But Shog9 is right when saying "let the browser do it for you..."
so.. here my edited version, using DOMParser:
function strip(html){
let doc = new DOMParser().parseFromString(html, 'text/html');
return doc.body.textContent || "";
}
here the code to test the inline javascript:
strip("<img onerror='alert(\"could run arbitrary JS here\")' src=bogus>")
Also, it does not request resources on parse (like images)
strip("Just text <img src='https://assets.rbl.ms/4155638/980x.jpg'>")
input element support only one line text:
The text state represents a one line plain text edit control for the element's value.
function stripHtml(str) {
var tmp = document.createElement('input');
tmp.value = str;
return tmp.value;
}
Update: this works as expected
function stripHtml(str) {
// Remove some tags
str = str.replace(/<[^>]+>/gim, '');
// Remove BB code
str = str.replace(/\[(\w+)[^\]]*](.*?)\[\/\1]/g, '$2 ');
// Remove html and line breaks
const div = document.createElement('div');
div.innerHTML = str;
const input = document.createElement('input');
input.value = div.textContent || div.innerText || '';
return input.value;
}
It is also possible to use the fantastic htmlparser2 pure JS HTML parser. Here is a working demo:
var htmlparser = require('htmlparser2');
var body = '<p><div>This is </div>a <span>simple </span> <img src="test"></img>example.</p>';
var result = [];
var parser = new htmlparser.Parser({
ontext: function(text){
result.push(text);
}
}, {decodeEntities: true});
parser.write(body);
parser.end();
result.join('');
The output will be This is a simple example.
See it in action here: https://tonicdev.com/jfahrenkrug/extract-text-from-html
This works in both node and the browser if you pack you web application using a tool like webpack.
For escape characters also this will work using pattern matching:
myString.replace(/((<)|(<)(?:.|\n)*?(>)|(>))/gm, '');
After trying all of the answers mentioned most if not all of them had edge cases and couldn't completely support my needs.
I started exploring how php does it and came across the php.js lib which replicates the strip_tags method here: http://phpjs.org/functions/strip_tags/
myString.replace(/<[^>]*>?/gm, '');
The above function posted by hypoxide works fine, but I was after something that would basically convert HTML created in a Web RichText editor (for example FCKEditor) and clear out all HTML but leave all the Links due the fact that I wanted both the HTML and the plain text version to aid creating the correct parts to an STMP email (both HTML and plain text).
After a long time of searching Google myself and my collegues came up with this using the regex engine in Javascript:
str='this string has <i>html</i> code i want to <b>remove</b><br>Link Number 1 -><a href="http://www.bbc.co.uk">BBC</a> Link Number 1<br><p>Now back to normal text and stuff</p>
';
str=str.replace(/<br>/gi, "\n");
str=str.replace(/<p.*>/gi, "\n");
str=str.replace(/<a.*href="(.*?)".*>(.*?)<\/a>/gi, " $2 (Link->$1) ");
str=str.replace(/<(?:.|\s)*?>/g, "");
the str variable starts out like this:
this string has <i>html</i> code i want to <b>remove</b><br>Link Number 1 -><a href="http://www.bbc.co.uk">BBC</a> Link Number 1<br><p>Now back to normal text and stuff</p>
and then after the code has run it looks like this:-
this string has html code i want to remove
Link Number 1 -> BBC (Link->http://www.bbc.co.uk) Link Number 1
Now back to normal text and stuff
As you can see the all the HTML has been removed and the Link have been persevered with the hyperlinked text is still intact. Also I have replaced the <p> and <br> tags with \n (newline char) so that some sort of visual formatting has been retained.
To change the link format (eg. BBC (Link->http://www.bbc.co.uk) ) just edit the $2 (Link->$1), where $1 is the href URL/URI and the $2 is the hyperlinked text. With the links directly in body of the plain text most SMTP Mail Clients convert these so the user has the ability to click on them.
Hope you find this useful.
https://developer.mozilla.org/en-US/docs/Web/API/Element/insertAdjacentHTML
var div = document.getElementsByTagName('div');
for (var i=0; i<div.length; i++) {
div[i].insertAdjacentHTML('afterend', div[i].innerHTML);
document.body.removeChild(div[i]);
}
A safer way to strip the html with jQuery is to first use jQuery.parseHTML to create a DOM, ignoring any scripts, before letting jQuery build an element and then retrieving only the text.
function stripHtml(unsafe) {
return $($.parseHTML(unsafe)).text();
}
Can safely strip html from:
<img src="unknown.gif" onerror="console.log('running injections');">
And other exploits.
nJoy!
Source: Stackoverflow.com