Extract element by ID from string?

Question

I have a string which contains this text:

Answer 1

You can create a temporary element, put the HTMLString as a content to it, then use querySelector to get an element with passed id. Something like this:

function ExtractElementByIdFromString(HTMLString, IdString) {
    var result,
        temp = document.createElement('div'); // Create a temporary element
    temp.innerHTML = HTMLString; // Set the passed string as HTML to the temporary element
    result = temp.querySelector('#' + IdString).outerHTML; // Find an element with the passed id
    return result;
}

A working demo at jsFiddle.