Get content within a tag using Javascript from HTML

I want a javascript code which will go through all the html file in my root folder and sub-folders and gets the content which are within a particul开发者_开发技巧ar tag, eg:

<div id="content">
!!this content!!
</div>

It should check for a comment at the top of html and only get the content if it exist.

<!--Allowed-->

It should only get if this is there. First of all is this possible? I wish jquery could do this!

Update: Got enlightened that javascript is for client-side! So One last question, how does you use php to get the content that is within the a particular tag?

    <div id="content">
    !!this content!!
    </div>

At first you have to get all the folders that are in the folder (on the server). That's not possible with JavaScript alone. You have to write a PHP (or any other web-language supported on your webspace/server) which gives you the filename-list. Then you can load each file with jQuery's ajax-functions and test for your comment, etc.

Javascript has no access to the file system. You need a server side language to do that.

No it is not possible with javascript. It is a client side scripting language. You need a serverside scripting language like PHP. Check out http://php.net/ look up the fopen(), include(), and dir() functions.

If you know the exact content of the comment you're searching for, try this:

if(document.documentElement.innerHTML.indexOf('<!--Comment-->') > 0){
    //voila!
}

If not, you can use regular expressions to parse the text. I'm not an expert in regex, so i can't say i can help you there.
Of course, this will only work on a per-page basis, it won't browse your file system. For that you should have a server-side language.
Hope this helps