Question

Basically I just need the effect of copying that HTML from browser window and pasting it in a textarea element.

For example I want this:

<p>Some</p>
<div>text<br />Some</div>
<div>text</div>

to become this:

Some
text
Some
text

Answer 1

If that HTML is visible within your web page, you could do it with the user selection (or just a TextRange in IE). This does preserve line breaks, if not necessarily leading and trailing white space.

UPDATE 10 December 2012

However, the toString() method of Selection objects is not yet standardized and works inconsistently between browsers, so this approach is based on shaky ground and I don’t recommend using it now. I would delete this answer if it weren’t accepted.

Demo: http://jsfiddle.net/wv49v/

Code:

function getInnerText(el) {
    var sel, range, innerText = "";
    if (typeof document.selection != "undefined" && typeof document.body.createTextRange != "undefined") {
        range = document.body.createTextRange();
        range.moveToElementText(el);
        innerText = range.text;
    } else if (typeof window.getSelection != "undefined" && typeof document.createRange != "undefined") {
        sel = window.getSelection();
        sel.selectAllChildren(el);
        innerText = "" + sel;
        sel.removeAllRanges();
    }
    return innerText;
}