How can I show HTML snippets on a webpage without needing to replace each < with < and > with >?
In other words, is there a tag for don't render HTML until you hit the closing tag?
The tried and true method for HTML:
Replace the & character with &
Replace the < character with <
Replace the > character with >
Optionally surround your HTML sample with <pre> and/or <code> tags.
sample 1:
<pre>
This text has
been formatted using
the HTML pre tag. The brower should
display all white space
as it was entered.
</pre>
sample 2:
<pre>
<code>
My pre-formatted code
here.
</code>
</pre>
sample 3:
(If you are actually "quoting" a block of code, then the markup would be)
<blockquote>
<pre>
<code>
My pre-formatted "quoted" code here.
</code>
</pre>
</blockquote>
is there a tag for don't render HTML until you hit the closing tag?
No, there is not. In HTML proper, there’s no way short of escaping some characters:
& as &
< as <
(Incidentally, there is no need to escape > but people often do it for reasons of symmetry.)
And of course you should surround the resulting, escaped HTML code within <pre><code>…</code></pre> to (a) preserve whitespace and line breaks, and (b) mark it up as a code element.
All other solutions, such as wrapping your code into a <textarea> or the (deprecated) <xmp> element, will break.1
XHTML that is declared to the browser as XML (via the HTTP Content-Type header! — merely setting a DOCTYPE is not enough) could alternatively use a CDATA section:
<![CDATA[Your <code> here]]>
But this only works in XML, not in HTML, and even this isn’t a foolproof solution, since the code mustn’t contain the closing delimiter ]]>. So even in XML the simplest, most robust solution is via escaping.
1 Case in point:
textarea {border: none; width: 100%;}
<textarea readonly="readonly">
<p>Computer <textarea>says</textarea> <span>no.</span>
</textarea>
<xmp>
Computer <xmp>says</xmp> <span>no.</span>
</xmp>
Kind of a naive method to display code will be including it in a textarea and add disabled attribute so its not editable.
<textarea disabled> code </textarea>
Hope that help someone looking for an easy way to get stuff done.
But warning, this won't escape the tags for you, as you can see here (the following obviously does not work):
<textarea disabled>
This is the code to create a textarea:
<textarea></textarea>
</textarea>
Deprecated, but works in FF3 and IE8.
<xmp>
<b>bold</b><ul><li>list item</li></ul>
</xmp>
Recommended:
<pre><code>
code here, escape it yourself.
</code></pre>
i used <xmp> just like this :
http://jsfiddle.net/barnameha/hF985/1/
The deprecated <xmp> tag essentially does that but is no longer part of the XHTML spec. It should still work though in all current browsers.
Here's another idea, a hack/parlor trick, you could put the code in a textarea like so:
<textarea disabled="true" style="border: none;background-color:white;">
<p>test</p>
</textarea>
Putting angle brackets and code like this inside a text area is invalid HTML and will cause undefined behavior in different browsers. In Internet Explorer the HTML is interpreted, whereas Mozilla, Chrome and Safari leave it uninterpreted.
If you want it to be non-editable and look different then you could easily style it using CSS. The only issue would be that browsers will add that little drag handle in the bottom-right corner to resize the box. Or alternatively, try using an input tag instead.
The right way to inject code into your textarea is to use server side language like this PHP for example:
<textarea disabled="true" style="border: none;background-color:white;">
<?php echo '<p>test</p>'; ?>
</textarea>
Then it bypasses the html interpreter and puts uninterpreted text into the textarea consistently across all browsers.
Other than that, the only way is really to escape the code yourself if static HTML or using server-side methods such as .NET's HtmlEncode() if using such technology.
If your goal is to show a chunk of code that you're executing elsewhere on the same page, you can use textContent (it's pure-js and well supported: http://caniuse.com/#feat=textcontent)
<div id="myCode">
<p>
hello world
</p>
</div>
<div id="loadHere"></div>
document.getElementById("myCode").textContent = document.getElementById("loadHere").innerHTML;
To get multi-line formatting in the result, you need to set css style "white-space: pre;" on the target div, and write the lines individually using "\r\n" at the end of each.
Here's a demo: https://jsfiddle.net/wphps3od/
This method has an advantage over using textarea: Code wont be reformatted as it would in a textarea. (Things like are removed entirely in a textarea)
In HTML? No.
In XML/XHTML? You could use a CDATA block.
I assume:
you want to write 100% valid HTML5
you want to place the code snippet (almost) literal in the HTML
especially < should not need escaping
All your options are in this tree:
with HTML syntax
there are five kinds of elements
those called "normal elements" (like <p>)
can't have a literal <
it would be considered the start of the next tag or comment
void elements
they have no content
you could put your HTML in a data attribute (but this is true for all elements)
that would need JavaScript to move the data elsewhere
in double-quoted attributes, " and &thing; need escaping: " and &thing; respectively
raw text elements
<script> and <style> only
they are never rendered visible
but embedding your text in Javascript might be feasable
Javascript allows for multi-line strings with backticks
it could then be inserted dynamically
a literal </script is not allowed anywhere in <script>
escapable raw text elements
<textarea> and <title> only
<textarea> is a good candidate to wrap code in
it is totally legal to write </html> in there
not legal is the substring </textarea for obvious reasons
escape this special case with </textarea or similar
&thing; needs escaping: &thing;
foreign elements
elements from MathML and SVG namespaces
at least SVG allows embedding of HTML again...
and CDATA is allowed there, so it seems to have potential
with XML syntax
covered by Konrad's answer
Note: > never needs escaping. Not even in normal elements.
It's vey simple ....
Use this xmp code
<xmp id="container">
<xmp >
<p>a paragraph</p>
</xmp >
</xmp>
<textarea ><?php echo htmlentities($page_html); ?></textarea>
works fine for me..
"keeping in mind Alexander's suggestion, here is why I think this is a good approach"
if we just try plain <textarea> it may not always work since there may be closing textarea tags which may wrongly close the parent tag and display rest of the HTML source on the parent document, which would look awkward.
using htmlentities converts all applicable characters such as < > to HTML entities which eliminates any possibility of leaks.
There maybe benefits or shortcomings to this approach or a better way of achieving the same results, if so please comment as I would love to learn from them :)
This is a simple trick and I have tried it in Safari and Firefox
<code>
<span><</span>meta property="og:title" content="A very fine cuisine" /><br>
<span><</span>meta property="og:image" content="http://www.example.com/image.png" />
</code>
It will show like this:
You can see it live Here
You could try:
Hello! Here is some code:
<xmp>
<div id="hello">
</div>
</xmp>
This is a bit of a hack, but we can use something like:
body script {
display: block;
font-family: monospace;
white-space: pre;
}
<script type="text/html">
<h1>Hello World</h1>
<ul>
<li>Enjoy this dodgy hack,
<li>or don't!
</ul>
</script>
With that CSS, the browser will display scripts inside the body. It won’t attempt to execute this script, as it has an unknown type text/html. It’s not necessary to escape special characters inside a <script>, unless you want to include a closing </script> tag.
I’m using something like this to display executable JavaScript in the body of the page, for a sort of "literate progamming".
There’s some more info in this question When should tags be visible and why can they?.
function escapeHTML(string)
{
var pre = document.createElement('pre');
var text = document.createTextNode(string);
pre.appendChild(text);
return pre.innerHTML;
}//end escapeHTML
it will return the escaped Html
Ultimately the best (though annoying) answer is "escape the text".
There are however a lot of text editors -- or even stand-alone mini utilities -- that can do this automatically. So you never should have to escape it manually if you don't want to (Unless it's a mix of escaped and un-escaped code...)
Quick Google search shows me this one, for example: http://malektips.com/zzee-text-utility-html-escape-regular-expression.html
This is by far the best method for most situations:
<pre><code>
code here, escape it yourself.
</code></pre>
I would have up voted the first person who suggested it but I don't have reputation. I felt compelled to say something though for the sake of people trying to find answers on the Internet.
You could use a server side language like PHP to insert raw text:
<?php
$str = <<<EOD
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="description" content="Minimal HTML5">
<meta name="keywords" content="HTML5,Minimal">
<title>This is the title</title>
<link rel='stylesheet.css' href='style.css'>
</head>
<body>
</body>
</html>
EOD;
?>
then dump out the value of $str htmlencoded:
<div style="white-space: pre">
<?php echo htmlentities($str); ?>
</div>
There are a few ways to escape everything in HTML, none of them nice.
Or you could put in an iframe that loads a plain old text file.
Actually there is a way to do this. It has limitation (one), but is 100% standard, not deprecated (like xmp), and works.
And it's trivial. Here it is:
<div id="mydoc-src" style="display: none;">
LlNnlljn77fggggkk77csJJK8bbJBKJBkjjjjbbbJJLJLLJo
<!--
YOUR CODE HERE.
<script src="WidgetsLib/all.js"></script>
^^ This is a text, no side effects trying to load it.
-->
LlNnlljn77fggggkk77csJJK8bbJBKJBkjjjjbbbJJLJLLJo
</div>
Please let me explain. First of all, ordinary HTML comment does the job, to prevent whole block be interpreted. You can easily add in it any tags, all of them will be ignored. Ignored from interpretation, but still available via innerHTML! So what is left, is to get the contents, and filter the preceding and trailing comment tokens.
Except (remember - the limitation) you can't put there HTML comments inside, since (at least in my Chrome) nesting of them is not supported, and very first '-->' will end the show.
Well, it is a nasty little limitation, but in certain cases it's not a problem at all, if your text is free of HTML comments. And, it's easier to escape one construct, then a whole bunch of them.
Now, what is that weird LlNnlljn77fggggkk77csJJK8bbJBKJBkjjjjbbbJJLJLLJo string? It's a random string, like a hash, unlikely to be used in the block, and used for? Here's the context, why I have used it. In my case, I took the contents of one DIV, then processed it with Showdown markdown, and then the output assigned into another div. The idea was, to write markdown inline in the HTML file, and just open in a browser and it would transform on the load on-the-fly. So, in my case, <!-- became transformed to <p><!--</p>, the comment properly escaped. It worked, but polluted the screen. So, to easily remove it with regex, the random string was used. Here's the code:
var converter = new showdown.Converter();
converter.setOption('simplifiedAutoLink', true);
converter.setOption('tables', true);
converter.setOption('tasklists', true);
var src = document.getElementById("mydoc-src");
var res = document.getElementById("mydoc-res");
res.innerHTML = converter.makeHtml(src.innerHTML)
.replace(/<p>.{0,10}LlNnlljn77fggggkk77csJJK8bbJBKJBkjjjjbbbJJLJLLJo.{0,10}<\/p>/g, "");
src.innerHTML = '';
And it works.
If somebody is interested, this article is written using this technique. Feel free to download, and look inside the HTML file.
It depends what you are using it for. Is it user input? Then use <textarea>, and escape everything. In my case, and probably it's your case too, I simply used comments, and it does the job.
If you don't use markdown, and just want to get it as is from a tag, then it's even simpler:
<div id="mydoc-src" style="display: none;">
<!--
YOUR CODE HERE.
<script src="WidgetsLib/all.js"></script>
^^ This is a text, no side effects trying to load it.
-->
</div>
and JavaScript code to get it:
var src = document.getElementById("mydoc-src");
var YOUR_CODE = src.innerHTML.replace(/(<!--|-->)/g, "");
This is how I did it:
$str = file_get_contents("my-code-file.php");
echo "<textarea disabled='true' style='border: none;background-color:white;'>";
echo $str;
echo "</textarea>";
It may not work in every situation, but placing code snippets inside of a textarea will display them as code.
You can style the textarea with CSS if you don't want it to look like an actual textarea.
If you are looking for a solution that works with frameworks.
const code = `
<div>
this will work in react
<div>
`
<pre>
<code>{code}</code>
</pre>
And you can give it a nice look with css:
pre code {
background-color: #eee;
border: 1px solid #999;
display: block;
padding: 20px;
}
JavaScript string literals can be used to write the HTML across multiple lines. Obviously, JavaScript, ECMA6 in particular, is required for this solution.
.createTextNode paired with CSS white-space: pre-wrap; does the trick.
.innerText alone also works. Run code snippet below.
let codeBlock = `
<!DOCTYPE HTML>
<html lang="en">
<head>
<title>My Page</title>
</head>
<body>
<h1>Welcome to my page</h1>
<p>I like cars and lorries and have a big Jeep!</p>
<h2>Where I live</h2>
<p>I live in a small hut on a mountain!</p>
</body>
</html>
`
const codeElement = document.querySelector("#a");
let textNode = document.createTextNode(codeBlock);
codeElement.appendChild(textNode);
const divElement = document.querySelector("#b");
divElement.innerText = codeBlock;
#a {
white-space: pre-wrap;
}
<div id=a>
</div>
<div id=b>
</div>
//To show xml tags in table columns you will have to encode the tags first
function htmlEncode(value) {
//create a in-memory div, set it's inner text(which jQuery automatically encodes)
//then grab the encoded contents back out. The div never exists on the page.
return $('<div/>').text(value).html();
}
html = htmlEncode(html)
A combination of a couple answers that work together here:
function c(s) {
return s.split("<").join("<").split(">").join(">").split("&").join("&")
}
displayMe.innerHTML = ok.innerHTML;
console.log(
c(ok.innerHTML)
)
<textarea style="display:none" id="ok">
<script>
console.log("hello", 5&9);
</script>
</textarea>
<div id="displayMe">
</div>
I used this a long time ago and it did the trick for me, I hope it helps you too.
var preTag = document.querySelectorAll('pre');
console.log(preTag.innerHTML);
for (var i = 0; i < preTag.length; i++) {
var pattern = preTag[i].innerHTML;
pattern = pattern.replace(/</g, "<").replace(/>/g, ">");
console.log(pattern);
preTag[i].innerHTML = pattern;
}
<pre>
<p>example</p>
<span>more text</span>
</pre>
You can separate the tags by changing them to spans.
Like this:
<span><</span> <!-- opening bracket of h1 here -->
<span>h1></span> <!-- opening tag of h1 completed here -->
<span>hello</span> <!-- text to print -->
<span><</span> <!-- closing h1 tag's bracket here -->
<span>/h1></span> <!-- closing h1 tag ends here -->
And also, you can just only add the <(opening angle bracket) to the spans
<span><</span> <!-- opening bracket of h1 here -->
h1> <!-- opening tag of h1 completed here -->
hello <!-- text to print -->
<span><</span> <!-- closing h1 tag's bracket here -->
/h1><!-- closing h1 tag ends here -->
<code><?php $str='<';echo htmlentities($str);?></code>
I found this to be the easiest, fastest and most compact.
I want to add another MSHTML question. Thanks to all responses.
We use in Delphi the standard TWebbrowser component, that uses mshtml.dll internally. Additionaly we use the registry to ensure that the pages renders with the new rendering engine (Web-Browser-Control-Specifying-the-IE-Version, MSDN: FEATURE_BROWSER_EMULATION). So we use the rendering of IE 10 but we have the same results with ie 8 to ie 11.
Using the standard rendering machine of MSHTML (IE7) works right, but due to new rendering options we need the new rendering of MSHTML.
We use the design mode of the control to enabled the user to make changes in the documents:
var
mDocument: IHTMLDocument2;
begin
mDocument := ((ASender as TWebBrowser).Document as IHTMLDocument2);
mDocument.designMode := 'on';
Now we have the following problem:
We load th following (simplified) HTML via the IPersistStreamInit.Load(...) into the WebBrowser:
<html>
<body>
What should I do
with some of the
spaces.
</body>
</html>
In the WebBrowser user can see the following:
Now, when selecting the word "with" in the WebBrowser in editing mode, and typing a character, some spaces appear. The HTML now has in it - exactly as many as there has been spaces in the HTML before editing:
The code is:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv="Content-Type" content="text/html; charset=unicode">
<META name="GENERATOR" content="MSHTML 10.00.9200.16540"></HEAD>
<BODY> What should I do n some of the spaces.
</BODY></HTML>
The same effect can be achieved by replacing the word "spaces" in the WebBrowser.
This is a bad behaviour for users using our application.
Every HTML code with white spaces infront of text, has the same behaviour. The mess is, that MSHTML itself generates such HTML.
By now we think of a solution to remove all the spaces on the left of each line, but we think that such workarounds could end in a bigger mess, because they change the HTML. This could cause some different behaviour of the rendering.
Thinking about removing the spaces before each line, puts you somewhere in the right direction, but nowhere near what you should be doing: convert the data info HTML before IPersistStreamInit.Load.
Since the HTML specification prescribes any whitespace in the HTML code should be treated as a single instance of whitespace (except inside <pre> tags), it's understandable that IE's design-mode is confused what to with these extra spaces when you edit around them. You've stumbled upon a border case.
I suggest you either don't use IPersistStreamInit.Load
but Navigate('about:<html><body></body></html>'); and document.body.innerText:=... instead,
or take care to properly format the initial HTML:
parse the text to collapse any/all consecutive whitespace,
replace all & with &, < with < etc...
(perhaps also #13#10 with '<br />' and #13#10#13#10 with '</p><p>'?)
Is it likely or possible for img tag, or any other to be parsed, when the < tag is several characters prior, or perhaps omitted? Would this happen in any notable HTML parsers?
For example
<div>$test</div>.
Where $test could be any string containing a >, but not a <. Such as img>, but not <img
Full disclosure: This question is specifically to see whether or not the comment I posted was correct.
You don't technically need either < or >. Load this up in IE, and it'll run a javascript alert. Not sure if it's possible without messing with the charset though.
<HTML>
<HEAD>
<META charset="UTF-7">
</HEAD>
<BODY>
<DIV>+ADw-script+AD4-alert(+ACI-XSS+ACI-)+ADw-/script+AD4-</DIV>
</BODY>
</HTML>
Source: http://securityoverride.org/articles.php?article_id=13
Well, out of curiosity, I changed one of my test pages so its script section began with this:
< script>
The result was completely broken and just printed all of my javascript. This happened in IE9, GC28, and Firefox. I didn't really have an image on-hand to test with, but I think we can derive from this that HTML tags are always required to have no white-space between the angle bracket and tag declaration.
If you'd like even further confirmation, I suggest you browse the W3C standardization documents to see if you can find where they declare the generic pattern for HTML element tags. Many HTML parsers probably base themselves off those documents to ease their coding.
White space is allowed after the tagname
< script> is invalid
while
<script> is valid
I need to insert HTML content into an XML document, is this possible or should HTML content be, for example, encoded in BASE64 or with something else like that?
You can include HTML content. One possibility is encoding it in BASE64 as you have mentioned.
Another might be using CDATA tags.
Example using CDATA:
<xml>
<title>Your HTML title</title>
<htmlData><![CDATA[<html>
<head>
<script/>
</head>
<body>
Your HTML's body
</body>
</html>
]]>
</htmlData>
</xml>
Please note:
CDATA's opening character sequence: <![CDATA[
CDATA's closing character sequence: ]]>
so long as your html content doesn't need to contain a CDATA element, you can contain the HTML in a CDATA element, otherwise you'll have to escape the XML entities.
<element><![CDATA[<p>your html here</p>]]></element>
VS
<element><p>your html here</p></element>
The purpose of BASE64 encoding is to take binary data and be able to persist that to a string. That benefit comes at a cost, an increase in the size of the result (I think it's a 4 to 3 ratio). There are two solutions. If you know the data will be well formed XML, include it directly. The other, an better option, is to include the HTML in a CDATA section within an element within the XML.
Please see this.
Text inside a CDATA section will be ignored by the parser.
http://www.w3schools.com/xml/dom_cdatasection.asp
This is will help you to understand the basics about XML
Just put the html tags with there content and add the xmlns attribute with quotes after the equals and in between the quotes is http://www.w3.org/1999/xhtml
How can you prevent any automatic formatting when in CKEditor when viewing in source mode?
I like to edit HTML source code directly instead of using the WYSIWYG interface, but whenever I write new lines, or layout tags how I would indent them, it all gets formatted when I switch to WYSIWYG mode and then back to source mode again.
I stumbled upon a CKEditor dev ticket, Preserve formatting of ProtectedSource elements, that alluded to a setting which may have existed once upon a time which would be exactly what I'm after. I just want to know how I can completely turn off all automatic formatting when editing in source mode.
I came up with a solution I thought would be foolproof (albeit not a pleasant one).
I learned about the protectedSource setting, so I thought, well maybe I can just use that and create an HTML comment tag before all my HTML and another after it and then push a regular expression finding the comment tags into the protectedSource array, but even that (believe it or not) doesn't work.
I've tried my expression straight up in the browser outside of CKEditor and it is working, but CKEditor doesn't protect the code as expected (which I suspect is a bug involving comment tags, since I can get it to work with other strings). In case you are wondering, this is what I had hoped would work as a work-around, but doesn't:
config.protectedSource.push( /<!-- src -->[\s\S]*<!-- end src-->/gi );
and what I planned on doing (for what appears to be the lack of a setting to disable formatting in source mode) was to nest all my HTML within the commented tags like this:
<!-- src -->
<div>some code that shouldn't be messed with (but is)</div>
<!-- end src -->
I'd love to hear if anyone has any suggestions for this scenario, or knows of a setting which I have described, or even if someone can just fill me in as to why I can't get protectedSource to work properly with two comment tags.
I really think it's gotta be a bug because I can get so many other expressions to work fine, and I can even protect HTML within the area of a single comment tag, but I simply cannot get HTML within two different comment tags to stay untouched.
My solution to this was to use comments in my system, but before feeding the page content to CKEditor, convert them to custom HTML tags. Then, upon save, convert them back to my comment tags.
For your syntax that would be something like this in PHP. Before printing the page content to the textarea:
$content = str_replace(array('<!-- src -->','<!-- end src -->'),array('<protected>','</protected>'),$content);
Before saving the resulting content:
$content = str_replace(array('<protected>','</protected>'),array('<!-- src -->','<!-- end src -->'),$content);
In the CKEditor configuration:
protectedSource:[/<protected>[\s\S]*<\/protected>/g]
Hope that helps!
I wanted to preserve newlines in my source, and the protectedSource feature works well for that. I added this to my config.js:
config.protectedSource = [/\r|\n/g];
config.allowedContent=true; will do the trick
Here is the full HTML code
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>CKEditor</title>
<script src="http://cdn.ckeditor.com/4.5.10/standard/ckeditor.js"></script>
</head>
<body>
<textarea name="editor1"></textarea>
<script>
CKEDITOR.config.allowedContent=true;
CKEDITOR.replace( 'editor1' );
</script>
</body>
</html>
I solved this problem by simply surrounding the back-end output of edit form page with a conditional on a $_GET variable - when you click on "Expert Mode" it loads a plain textarea instead of the ckeditor system. Your invocation of the ckeditor object will vary depending on your setup. ( I have a custom class that calls/builds the editor object )
<div id="postdivrich" class="postarea">
<?php
if( isset( $_GET['expert'] ) )
{
print "<div style=\"text-align:right;\">Editor mode</div>\n";
print "<textarea name=\"content\" style=\"height:400px;width:{$nEwidth}px;\">{$aDoc['content']}</textarea>\n";
}
else
{
print "<div style=\"text-align:right;\">Expert mode</div>\n";
require_once( 'admin/editor.class.php' );
$aDoc['content'] = str_replace( "\r", '', str_replace( "\n", '', nl2br( $aDoc['content'] ) ) );
$oEditor = new setEditor( $aDoc['content'], $nEwidth, "400", 'content' );
$oEditor->ShowEditor();
}
?>
</div>
Does this answer help? Basically you can turn off the options adding a javascript, it looks like.