Can you use jquery to add comments dynamically to code?

Question

I tried:

<script>
$(function() {
$('.class').before('<!--');
$('.class').after('-->');
});

</script>

but it didn't work for a reason unknown to me.

Can anyone help me understand why it didn't work and how I would do it? Thank you, much appreciated.

Answer 1

It looks like you're trying to make objects with .class disappear. Use .hide() instead. Comments are only parsed when the browser first loads the page, so adding comments won't comment something out.

You need to learn the difference between HTML and the DOM. HTML is the textual representation of the page, but the browser parses it into the DOM on page load. JavaScript works on the DOM, not on the HTML. Using .innerHtml() on DOM elements reparses the HTML.

Here's an example of using innerHtml() to hide elements using HTML comments (but note that I would never do this - I'm only showing how to do what it looked like you were trying to do in your question):

HTML:

<h1>hello</h1>

<div>
    <p>wow</p>
    <p>dude</p>
</div>​

JavaScript (+ jQuery):

$(document).ready(function () {
    setTimeout(hideIt, 1000);
});

function hideIt() {
    $('div').html('<!--' + $('div').html() + '-->');
}​

Answer 2

You're mixing two completely unrelated concepts there: HTML and the DOM.

HTML is a textual means of describing content, which — like code — has a means of commenting things out. The DOM is the resulting object model in the browser.

Once the HTML has been read and parsed and the DOM has been created, the HTML is discarded and unnecessary. Adding HTML comments to things won't change them, and in fact doesn't make sense (although it's easy to see how you thought it would, don't get the wrong idea).

Once you have the DOM, to hide an element without removing it, use hide. To remove it entirely, use remove.

Live examples of both: http://jsbin.com/araju