Rendering HTML inside textarea

Question

I need to be able to render some HTML tags inside a textarea (namely , , , ) but textareas only interpret their content as text. Is

Answer 1

Since you only said render, yes you can. You could do something along the lines of this:

function render(){
	var inp     = document.getElementById("box");
	var data = `
<svg xmlns="http://www.w3.org/2000/svg" width="${inp.offsetWidth}" height="${inp.offsetHeight}">
<foreignObject width="100%" height="100%">
<div xmlns="http://www.w3.org/1999/xhtml" 
style="font-family:monospace;font-style: normal; font-variant: normal; font-size:13.3px;padding:2px;;">
${inp.value} <i style="color:red">cant touch this</i>
</div>
</foreignObject>
</svg>`;
	var blob = new Blob( [data], {type:'image/svg+xml'} );
	var url=URL.createObjectURL(blob);
	inp.style.backgroundImage="url("+URL.createObjectURL(blob)+")";
 }
 onload=function(){
  render();
  ro = new ResizeObserver(render);
	ro.observe(document.getElementById("box"));
 }

#box{
  color:transparent;
  caret-color: black;
  font-style: normal;/*must be same as in the svg for caret to align*/
  font-variant: normal; 
  font-size:13.3px;
  padding:2px;
  font-family:monospace;
}

<textarea id="box" oninput="render()">you can edit me!</textarea>

This makes it so that a textarea will render html! Besides the flashing when resizing, inability to directly use classes and having to make sure that the div in the svg has the same format as the textarea for the caret to align correctly, it's works!

Answer 2

try this example

function toggleRed() {
  var text = $('.editable').text();
  $('.editable').html('<p style="color:red">' + text + '</p>');
}

function toggleItalic() {
  var text = $('.editable').text();
  $('.editable').html("<i>" + text + "</i>");
}

$('.bold').click(function() {
  toggleRed();
});

$('.italic').click(function() {
  toggleItalic();
});

.editable {
  width: 300px;
  height: 200px;
  border: 1px solid #ccc;
  padding: 5px;
  resize: both;
  overflow: auto;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="editable" contenteditable="true"></div>
<button class="bold">toggle red</button>
<button class="italic">toggle italic</button>

Answer 3

This is not possible to do with a textarea. What you are looking for is an content editable div, which is very easily done:

<div contenteditable="true"></div>

jsFiddle

div.editable {
    width: 300px;
    height: 200px;
    border: 1px solid #ccc;
    padding: 5px;
}

strong {
  font-weight: bold;
}

<div contenteditable="true">This is the first line.<br>
See, how the text fits here, also if<br>there is a <strong>linebreak</strong> at the end?
<br>It works nicely.
<br>
<br><span style="color: lightgreen">Great</span>.
</div>

Answer 4

With an editable div you can use the method document.execCommand (more details) to easily provide the support for the tags you specified and for some other functionality..

#text {
    width : 500px;
	min-height : 100px;
	border : 2px solid;
}

<div id="text" contenteditable="true"></div>
<button onclick="document.execCommand('bold');">toggle bold</button>
<button onclick="document.execCommand('italic');">toggle italic</button>
<button onclick="document.execCommand('underline');">toggle underline</button>

Answer 5

This is possible with <textarea> the only thing you need to do is use Summernote WYSIWYG editor

it interprets HTML tags inside a textarea (namely <strong>, <i>, <u>, <a>)

Answer 6

An addendum to this. You can use character entities (such as changing <div> to <div>) and it will render in the textarea. But when it is saved, the value of the textarea is the text as rendered. So you don't need to de-encode. I just tested this across browsers (ie back to 11).